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Title: Easy: Knight and Dragon Post by bob dodge on Jul 27th, 2002, 3:44am A dragon and knight live on an island. This island has seven poisoned wells, numbered 1 to 7. If you drink from a well, you can only save yourself by drinking from a higher numbered well. Well 7 is located at the top of a high mountain, so only the dragon can reach it. One day they decide that the island isn't big enough for the two of them, and they have a duel. Each of them brings a glass of water to the duel, they exchange glasses, and drink. After the duel, the knight lives and the dragon dies. Why did the knight live? Why did the dragon die? Note: From a Trilogy interview. I haven't solved this one yet. Here is how my thinking goes. The knight presents the dragon with a glass of normal water. The dragon assumes he is getting poisoned water, and immediately runs to well 7, and drinks. He does this because well 7 will neutralize the poison from any tainted well the knight can reach. Now, because he had never poisoned himself before, rather than neutralizing the poison of a lesser well, the water of 7 will kill the dragon, as there is no cure, as there is no well numerically higher than 7. now, for the knight part. why wouldn't the dragon give the knight well 7 water? if the dragon did give knight well 7 water the knight would die too. I am suspicious that the dragon agrees to not give well 7 water as the knight cannot reach well 7. Even so, why can't the dragon give the knight water from well 6, in which case the knight would die too. |
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Title: Re: Easy: Knight and Dragon Post by yasonf on Jul 27th, 2002, 4:22am here is what I believe to be the solution: assuming that both the knight and dragon die immediately after the duel, and can't drink another glass of water... before the duel, the knight drinks from any of the wells (except number 7), then heads to the duel. The knight brings with him a glass of number 1. The dragon, thinking that since only he can get to number 7, brings number 7 to the duel. When they trade glasses, the number 7 that the knight drinks, cancels the number 1 he drank earlier and he is cured. The dragon drinks the number 1 and then dies. This all assumes that, theoretically, if the duel were done without anything done before hand (i.e. the knight drinking number 1), then they would both die, because neither of them would have access to a higher well immediately. If the poison takes a while to kill you, then the dragon could, in both situations, fly to the 7th well, and drink and live; then they would be back in the same situation as the beginning. Giz |
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Title: Re: Easy: Knight and Dragon Post by Ion Rush on Jul 27th, 2002, 4:34am yea, I posted this earlier but under a different name (I was sloppy with the roll down fields) yep, I can see that, the knight drinks poison from well 1, but gives clean water, assuming the dragon will immediately go to well 7 and drink thinking he is poisoned. unfortunately, if the knight can think forward, why can't the dragon, and as the knight predicts the dragon's act of giving him well 7 water and assuming his own cup is tainted, going straitght to 7, why can't the dragon also figure this out. Then the dragon would offer the knight water from well 1, and the dragon would not attempt to neutralize his own poison, has he figures the knight slipped him clean water. well 1 water would not neutralize poison from well 1, but the knight wouldn't realize this, and die |
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Title: Re: Easy: Knight and Dragon Post by Kozo Morimoto on Jul 27th, 2002, 6:12am I can see a scenario where the Dragon can guarantee 100% survival but not for the Knight. Dragon turns up by drinking from well 1 before hand. a) Knight turns up with clean water. Dragon goes drinks from well 1 (drinking more doesn't do anything), then drinks from well 7. b) Knight turns up with water from well 1. Dragon goes drinks from well 1 (drinking well 1, 3 times won't do anything), then drinks from well 7. c) Knight turns up with water from well 2 to 6. (Dragon is cured now) But Dragon goes and drinks from well 1 to REPOISON himself then drinks from well 7 to neutralize. So in all scenarios, Dragon drinks from well 1 prior to duel then goes back and drinks from well 1, followed by well 7 to guarantee survival. However there are no 100% survival scenarios for the Knight. |
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Title: Re: Easy: Knight and Dragon Post by yasonf on Jul 28th, 2002, 12:38am OK, here is another idea... Before the competition, the knight drinks from well 1. The knight brings a glass with water from two wells, lets say wells 1 and 2. The dragon brings a glass of number 7 to the duel. At the duel, they trade and the knight drinks number 7 which nutralizes the number 1 he drank earlier, so he is safe. The dragon drinks the mix if 1 and 2. The dragon then knows that the only way to negate this drink is to go to number 7 well and drink. He drinks number 7 but it only poisons him because the mixture he drank before was a nutralized glass of water. |
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Title: Re: Easy: Knight and Dragon Post by Princeton on Jul 28th, 2002, 9:19pm The knight gives the dragon a glass of plain water. The dragon gives the knight water from well 1 through 6. The knight rides on the dragons back up to well 7. They then both drink from well 7. This in fact poisons the dragon, but cures the knight. The problem doesn't say the dragon is smart. Maybe he's too lazy to fly up to the mountain twice in one day, so he just uses well 6, figuring it will kill the knight just as surely as well 7. Folks, ya gotta think outside the box if you want to work at Trilogy. |
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Title: Re: Easy: Knight and Dragon Post by jmlyle on Jul 28th, 2002, 10:33pm This is one of those problems that I like to figure out, what is extraneous? Like the Funkytown-hair problem, it might be easier to think about with less information (4 instead of 483,207 works just as well). I think that 7 wells are many more than are needed. I think that three wells total should provide the exact same situation, but it might require four, if it's more complicated that I'm thinking. Frankly, the way the question is worded seems far too simple for the problem. The actual question is basically only asking, "What is a sceanrio in which the knight lives and the dragon dies?" A possible answer to this question is: Knight drinks water from well 5 before the duel Knight brings water from well 6 Dragon brings water from well 7 Knight is cured by water from well 7. Dragon forgets to drink from well 7 and dies. -- jmlyle |
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Title: Re: Easy: Knight and Dragon Post by Tom on Jul 30th, 2002, 8:35am Here's my answer: The knight drank from well 1 before the duel and took plain water. The dragon took water from well 7. After the duel he drank from well 7 assuming it would cure him from well 1-6. The knight was cured by well 7 and the dragon was poisoned by well 7. The question didn't ask for a scenario in which the knight would always live and the dragon would always die. The question simply wanted to know how it could have happened that the knight lived and the dragon died. There is more than one answer, and none are absolute. |
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Title: Re: Easy: Knight and Dragon Post by cnmne on Jul 30th, 2002, 1:37pm I think that the question is simplistic and expects a simplistic answer. The person writing the interview was not as smart as the person they were hiring, so it is a real world example and the interviewee had to account for that. The knight drank water from well 1 before the duel and brought plain water, assuming the dragon would bring water from well 7 and drink well 7 water after. The knight assumes that the powerful dragon has the brains of a bully and turns out to be right. |
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Title: Re: Easy: Knight and Dragon Post by Daishi on Jul 30th, 2002, 10:29pm Question: If the knight could bring plain water, why were they drinking from poisoned wells in the first place? |
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Title: Re: Easy: Knight and Dragon Post by Blender on Jul 31st, 2002, 1:15pm No problem. The knight drinks a glass of the all-powerful antidote before the duel. He brings a glass of water from well 1. Since all the wells are poison, then the dragon, drinking from 7, still dies. The knight has the antidote and lives. How does the knight get the antidote? The same way all the rest of you are fabricating the 'plain water' that isn't described in the original riddle. Now, has anyone solved this with just the items described in the riddle? |
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Title: Re: Easy: Knight and Dragon Post by Ion Rush on Jul 31st, 2002, 9:11pm "Knight is cured by water from well 7. Dragon forgets to drink from well 7 and dies. " but you are specifically given the information that ONLY the dragon can reach well 7. also, they want to get rid of eachother, enough so they want to kill eachother. why the hell would the dragon carry the knight to well 7??? as far as implying nonpoisonous water...you are right, the riddle doesn't say that there is no pure water, but we can infer that their is, otherwise there would be no need for a duel, because each would soon die from dehidration. (drink well 1 on day one, well 2, etc etc, until well 6 or 7 -depending on your flight ability - then what ? die from dehidration. If you can drink from well 1 then neutralize it with water from well 2, you also have access to nonpoisonous water by mixing the 2 |
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Title: Re: Easy: Knight and Dragon Post by jmlyle on Jul 31st, 2002, 11:23pm Ion, you need to read a little more carefully. You asked: Quote:
What I had said was: Quote:
--jmlyle |
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Title: Re: Easy: Knight and Dragon Post by blender on Aug 1st, 2002, 8:56am ok. So if you all are of the opinion that it's safe to fabricate the pure water, then I believe I can solve the riddle in a more obvious and 'clean' way. Basic tenets: The riddle says "there are seven poisoned wells". We accept that there is other pure water available. Now, since all the wells are poisoned, then it must be the case that anyone drinking from well 7 will be poisoned and since there is no well 8, then they will die. Both knight and Dragon. So the knight brings pure water _and_ water from some random well. The dragon brings water from some other random well. They switch glasses. The dragon drinks from the glass provided by the knight. The knight drinks some pure water (because the riddle states that the knight does indeed drink something but doesn't say _what_). The dragon realizes he's been poisoned and goes through the various wells, finally drinking from #7 and dies. The knight didn't drink any poisoned water and lives. Easy. |
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Title: Re: Easy: Knight and Dragon Post by jmlyle on Aug 1st, 2002, 9:15am blender, you're kidding, right? Even if you're not, this doesn't require there being any pure water available at all. If the knight is able to distract the dragon enough that he can switch glasses to one that he has hidden under his helmet (HEY! What's that behind you?!), then he can just drink a glass of water from 1 and later go over and have a sip from 2. In fact, he could just distract the dragon again (WAIT! There it is again! Look! I'm serious!), and then swap for yet another glass of water from 2 that he has hidden in his cod piece. |
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Title: Re: Easy: Knight and Dragon Post by James G on Aug 1st, 2002, 9:09pm Well... The way I read the riddle was that drinking from a well, then a higher numbered one cancels the poison completely. ie. both the knight and dragon could live on the island without dehydrating by drinking well 1 water and chasing it up with well 2 water (or chasing up well 3 water with well 6, or well 1 with well 7, or whatever). I don't think there's supposed to be any kind of chain effect, where someone drinks from well 1, then has to drink from 2, then has to drink from 3, etc. After all, if there was, what would be the point in the duel? Both could kill the other. (I know this concept is somewhat bizzare, but I think that's how the riddle is intended.) But regardless of whether there is any clean water available, I think it would be against the rules of the duel to bring clean water. (That's the way I read it.) I'm assuming that well 7, which is impossible for the knight to reach, is also time-consuming for the dragon to reach, and that all the other wells are easily accessible. (Not specifically stated in the question, but seems to be implied?) And I'm assuming that the knight is smarter than the dragon. This seems reasonable, since the knight lived and the dragon didn't, even though the dragon had more resources available. So... the dragon decided to bring either well 7 or well 6 water. It knew that the knight wouldn't be be able to reach a higher number well, and also knew that whatever water the knight brought, well 7 would neuturalise it. The knight anticipated the dragon's thinking, brought water from one of wells 1 to 5, and drank a little of it before the duel. (Or maybe got water from well 6, and drank some water from well 1 before the duel, if that's possible. Or maybe got water from well 6, and drank a little of it before the duel, if they assumed the dragon would bring from well 7.) Hence the knight lived. The dragon, having drank poison water, now heads off for well 7, but dies before getting there. (Or realises they can't make it, and drinks from well 6 instead perhaps, if the knight had brought well 6 water.) Too many assumptions? It seems plausible though. |
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Title: Re: Easy: Knight and Dragon Post by smst on Aug 2nd, 2002, 5:29am No pure water required for this to have worked. To give us the outcome given in the riddle, we just have the knight bring some water from #1-#6 (any one is fine) and the dragon bring some water from a higher well (#7 is ideal). The knight sips some water before they meet, they switch glasses, and the higher-numbered water neutralises anything the knight has already drunk. The low-numbered water kills the dragon (even if he'd sipped some higher-numbered stuff beforehand, it wouldn't have helped). It seems that we're not being asked to come up with a strategy which guarantees a win for the knight -- just to hypothesise on what could have happened. I reckon the point of the riddle is to get you to say "the knight drank something before the duel", with which will come the zen-like enlightenment that the water drunk during the duel will have become a cure, not a poision. |
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Title: Re: Easy: Knight and Dragon Post by kybernetikos on Aug 2nd, 2002, 6:23am Can't the knight guarantee survival by drinking from well #1 before the contest and then after the contest drinking more from well #1, then drinking from well #2. The dragon can't guarantee survival, because he doesn't know if the knight has poisoned him or not. Even drinking from all the wells in sequence doesn't help, because there's an odd number of wells. The best the dragon can do is 50% chance of survival, while the knight can be sure he'll survive. |
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Title: Re: Easy: Knight and Dragon Post by Mortimer on Aug 8th, 2002, 1:09am I'm assuming the dragon's smart, but doesn't understand duplicity. The knight, being human, knows how to cheat. Tom was the first to post the right answer. Before the duel, the knight drank from any of the wells 1-6, probably 1. The dragon brought 7 to the duel, which the knight then drank as the antidote. The knight brought plain water to the duel, the dragon believed it was 1-6, so after the duel, the dragon flew back up and drank from well 7, thus killing himself. How did the knight get plain water? There might be an unpoisoned well around. If not that, he could have possibly mixed the water from well 1 with a higher water. Or he could have simply spat into the cup until it was full. Failing all these, they're on an island. If it's in a fresh water lake, he could just go down to the beach and fill the glass. If it's salt water, he could filter out the fresh water by building a fire, pouring salt water into it, and collecting the steam or something. Or maybe it rained before the duel. Pick a method, or invent your own. The solution's the only possible one. |
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Title: Re: Easy: Knight and Dragon Post by Charlie Dobbie on Aug 9th, 2002, 12:59am My answer is maybe a bit of a cheat, but I submit it here for your approval: At the duel the Dragon is sure to have brought water from well 7 as it's the only advantage he has. (Assumption 1: The Dragon acts intelligently.) The Knight brings whatever water he can, water from well 1 would do. It doesn't matter. At the time of the duel, both parties are getting ready to drink. If the duel went ahead like this, both would live immediately after the duel (Assumption 2: The poison's effects are not immediate, as must be if you can be cured,) although both would be poisoned. After the duel, the Knight can drink from any of wells 1-6 to cure himself, while the Dragon can drink from any of wells 1-7. As the Knight cannot reach well 7 it can be considered an antidote to anything the Knight gives the Dragon (Assumption 3: The poisoned party can tell they've been poisoned.) As the Dragon can reach the highest well, the Knight cannot survive if it gets water from there. My answer is that the Knight raises the glass but does not drink, and when the Dragon raises his water to his lips (Assumption 4: Dragons have lips...), the Knight draws his sword and stabs him. My thought is that as either party can drink beforehand, and neither party know what water they are presented with, there are many different possible outcomes, none of which yield a guaranteed success for the Knight. Thus, the only way to win is not to play. How about that? |
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Title: Re: Easy: Knight and Dragon Post by Just a guy on Aug 13th, 2002, 9:18pm Ok, the way I figure is that the knight drank from well one before hand knowing well that the dragon would give him water from six or seven. The knight then can bring the dragon water from well 1 or any of the other five he can reach. After they drink, they DUEL, so the dragon has no chance of leaving and going to a well. Then the dragon dies and the knight survives. |
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Title: Re: Easy: Knight and Dragon Post by Brian Reynolds on Aug 23rd, 2002, 6:54am I agree with Mortimer -> the problem states that they're on an -island- with seven poisoned wells, so "clean" water is in fact one of the items mentioned in the riddle and "island" is just the sneaky way of getting it in there. These solutions are supposed to be "elegant" and "sexy" and the clean water solution is just that. So: Knight sips from well 1 beforehand and gives the dragon a glass of clean water. Dragon gives knight a glass of well 7, which curest the knight, and then rushes to drink from well 7, thinking it will cure him of whatever the knight gave him. But since the knight didn't give the dragon poisoned water, drinking from well 7 -poisons- the dragon, and since there's no higher numbered well, the dragon dies. This is additionally elegant because it fits with the traditional stereotypes for knights and dragons -- the dragon tries to do the most evil thing possible, and the knight is able to win without having to poison his foe -- the dragon poisons himself! Okay, so I didn't pee in my pants but it's pretty elegant. |
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Title: Re: Easy: Knight and Dragon Post by Guest on Aug 25th, 2002, 12:17am As others have said, it's possible for both the knight and dragon to guarantee that they will live, even if the opponent will not die. Both drink from well 1 before the dual, bring whatever they want in a glass to the dual, drink the opponents glass, drink again from well 1, and then drink from well 2. This guarantees they never drink a higher poison than they can cure, unless they are drinking the opponents glass which would cure their well 1 poison. The only solution is that the dragon was stupid. Maybe a better riddle would have been "Where did they get the glasses?" |
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Title: MISDIRECTION Post by Marc Nielsen on Nov 7th, 2002, 4:20am Quote:
I believe you are correct - the knight draws his sword and kills the dragon Explanation follows... Quote:
Although, I wouldn't say that the knight had to switch water you are on the right track. Distraction - or rather misdirection. If we take a look at the riddle once more (interesting parts hihglighted): A dragon and knight live on an island. This island has seven poisoned wells, numbered 1 to 7. If you drink from a well, you can only save yourself by drinking from a higher numbered well. Well 7 is located at the top of a high mountain, so only the dragon can reach it. One day they decide that the island isn't big enough for the two of them, and they have a duel. Each of them brings a glass of water to the duel, they exchange glasses, and drink. After the duel, the knight lives and the dragon dies. Why did the knight live? Why did the dragon die? *** Who says that the duel is the exchange of water??? It could just be plain water (in case they needed refreshment) - the riddle doesn't state that the two parties bring water from a poisened well. The riddle doesn't state that the water exchange is the duel, either (and I don't asssociate a duel with an exchange of water.) The answer: They drink the water and in the following duel the knight kills the dragon. Anyway; as we don't get enough information from the riddle (we have to make assumptions) the answer is blowing in the wind. (ie. a given answer just has to be well argued for) regards Marc Nielsen |
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Title: Re: Easy: Knight and Dragon Post by Jeremy on Nov 7th, 2002, 5:43am If you want to cling to that answer, go for it. But it really ignores all the original parameters of the riddle, and makes the same assumptions that the "clever" solution makes. I hold with Tom's solution. The knight drinks from a poisoned well before hand, and the dragon's glass cures him. The knight brings a non-poisoned glass, and the dragon (thinking he needs to cure himself) drinks from well 7, and dies. No non-poisoned water you say? the night can get some sea water.... i'm sure poisoned water isn’t' supposed to taste good either. |
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Title: Re: Easy: Knight and Dragon Post by 73 Hands on Nov 12th, 2002, 12:45am If anyone is concerned about pure water being used, why couldn't the knight have brought some water with a mixture of wells 1 and 2? He must have some way of drinking water and not dying. I don't see how mixing the water in a cup and in a stomach is very diffrent. If you want I'll add that water was poured into the cup from well one first and then water from well two was added after. |
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Title: Re: Easy: Knight and Dragon Post by Time on Nov 13th, 2002, 12:37am All of your answers are just hypothetical, and it doesn't have any real proof. In conclusion, I do believe that there is no wrong answer for this question. Unless, you give a really dumb answer. ;D |
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Title: Re: Easy: Knight and Dragon Post by Sylvie Tsie on Nov 26th, 2002, 6:56am You're all wrong. The knight drinks from Wel number one, and brings normal water. Because the knight has honor. The dragon is a sly creature, and brings water one to seven. And poisons the knight. Then The knight kills the dragon, because duels only end after someone dies. |
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Title: Re: Easy: Knight and Dragon Post by TenaliRaman on Jun 6th, 2003, 11:29pm Of all the above solution which one is right ??? (i can't make out) But the solution provided James G seems appropriate and seems to be within the constraints of the problem. |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Jun 7th, 2003, 2:29pm There is no single "right" answer to this riddle. As has been shown (I think in this thread, though I didn't see it in my quick scan - but it may be in one of the other threads for this riddle), both the knight and the dragon can insure their own survival. That the dragon dies tells you that he didn't figure out how. Thus it becomes a matter of choosing which of the many errors possible is the one that the dragon makes. The real puzzle here is to figure out how the knight can survive (the "preemptive self-poisoning" trick). Once you know that, then you can come up with a number of scenarios that match the puzzle. |
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Title: Re: Easy: Knight and Dragon Post by TenaliRaman on Jun 8th, 2003, 9:17am on 06/07/03 at 14:29:22, Icarus wrote:
I quite realised that when i was working with the problem but i was simply searching for the scenario which remains very much inside the frame of the question. |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Jun 8th, 2003, 8:42pm on 06/08/03 at 09:17:59, TenaliRaman wrote:
And what I am saying is that there are MANY scenarios which remain very much inside the frame of the question. The one thing they have in common is that the Knight pre-poisons himself. Beyond that there is a great deal of freedom inside the frame of the question to create plausible courses of events. |
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Title: Re: Easy: Knight and Dragon Post by TenaliRaman on Jun 8th, 2003, 9:46pm Ofcourse! Cheers!!! :) |
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Title: Re: Easy: Knight and Dragon Post by Lillith on Sep 18th, 2003, 3:38am Well, if any of both drinks water of well, let's say,1 and after that,to cure himself, well 2, doesn't he get poisoned by well 2 that way? And if this is so, the knight can give any water to the dragon to kill the beast and just NOT DRINK THE WATER the dragon gives to him. Correct??? |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Sep 18th, 2003, 3:34pm When I first read this puzzle, I thought the same thing. The puzzle is not well-stated in my opinion. But reading the discussion, it becomes clear that the INTENT was: if you are poisoned by a lower number well, drinking water from any higher well will cure you, not poison you. It is only when you are not poisoned already that the higher numbered well water will poison you. |
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Title: Re: Easy: Knight and Dragon Post by TuCelts on Nov 6th, 2003, 10:56pm I rather feel that the INTENT of this brain teaser (not a true puzzle since it has no concrete solution) was to mislead and or to tease people mercilessly. If you begin by looking at the stated facts you see several gaps. Facts, as stated, are: a dragon and knight reside on one island; there are 8 sources of liquid including the 7 poisonous wells and the liquid around the island; each poisonous well can be cured only by the liquid of a higher well, indicating that well 1 is cured by all others and 7 is cured by none; only the dragon can reach well 7; the knight and dragon both bring a glass of water; both duellists drink from the other's glass; the dragon dies. Everything else is done on an assumption. Try assuming that there isnt even water in the wells, as the "puzzle" never said what kind of well they are. Assume, for the fun of it, that they are oil wells :o. The water comes from another source and the duel is a physical contest and knight kills dragon. Or, again just for the fun of it, assume the water is safe, or they took precautions as suggested by some. The duel ends in a draw, and the dragon flies away to his mountainous home, and accidentally drinks from well 7, poisoning himself. At this point there are only two real questions left: 'How many ways can I work this out?' and 'How long will people keep debating the relative merits of the various points of view?'. |
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Title: Re: Easy: Knight and Dragon Post by simX on Apr 11th, 2004, 2:44am There's one thing I'd like to point out for all of those that think bringing a mix of any two wells will do the trick. Consider: drinking first from well 1 poisons, then drinking from well 2 cures. But when drinking first from well 2 poisions, drinking from well 1 afterwards does NOT cure. But if you assume that the cure happens simply by neutralizing of the two poisons in the stomach by mixing, then you'd have to conclude that drinking from any well will cure the poisoning from any other well (which is clearly a contradiction from the riddle). (You COULD say that there's some fundamental difference between pouring water from well 1 into water from well 2 and pouring water from well 2 into well 1 such that only the former will create benign water, but I think that's way too far fetched even for some of the suggestions in this thread. :) ) Stated another way: since drinking first from 1 then from 2 leaves you alive, but drinking first from 2 then from 1 leaves you dead (assuming you don't do anything else), the cure cannot possibly come from mixing since if it did, both situations would leave you alive. So the assumption that the curing happens by mixing in the stomach is a fallacy. Therefore, I believe that the only reasonable solution to the problem involves [HIDE]the knight bringing benign water that comes from around the island, not from any of the wells[/HIDE]. |
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Title: Re: Easy: Knight and Dragon Post by towr on Apr 11th, 2004, 7:32am on 04/11/04 at 02:44:13, simX wrote:
It's still a contradiction, but a weaker one. |
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Title: Re: Easy: Knight and Dragon Post by simX on Apr 11th, 2004, 1:04pm on 04/11/04 at 07:32:59, towr wrote:
But by extension, you can apply this to all pairs of wells. Given any pair of wells, one well will have a higher number and therefore neutralize the lower one. But if neutralization happens by mixing, then the lower one would also neutralize the higher one. So since we can extend this fact to all pairs of wells, it means that any well can be neutralized by any other well. |
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Title: Re: Easy: Knight and Dragon Post by towr on Apr 11th, 2004, 2:42pm on 04/11/04 at 13:04:14, simX wrote:
I'm really doing a particularly bad job at reading the problems today it seems.. |
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Title: Re: Easy: Knight and Dragon Post by rmsgrey on Apr 19th, 2004, 5:14am One possible mechanism to account for the higher-number antidote phenomenon would be the "water" from each well containing an active ingredient that breaks down over time - the break-down product is toxic, and the initial state non-toxic, and the intial state of any higher numbered well reacts with the breakdown product of any lower numbered well to neutralise both (in such a way that proportions needn't be exact) |
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Title: Re: Easy: Knight and Dragon Post by grimbal on Apr 22nd, 2004, 3:26pm If the dragon is allowed to go drinking after the duel, he just drinks the water that is given to him. Then, he goes drink from well 6, well 6 again and well 7. If the knight's water is from well 1 to 5, then well 6 cures him, then 6 poisons him again and 7 cures him. If the water was from well 6, well 6 doesn't cure him and well 7 cures him. If the original water was clear, well 6 poisons him and well 7 cures him. So, it seems they are not allowed to drink afterwards. But then, whoever brings water from well 1 kills his opponent. If they are healthy, it will poison them. If they are not, it will not cure them. So there is not solution. It would make sense if they switch glass twice. They bring water, switch glasses, drink, switch again and drink again. It is like a contest of who can provide the more powerful water. Then what happened is that the dragon brought water from well 7, thinking he could not be beaten, while the knight, realizing that it wouldn't do, decided to drink water from well 1 and then brought a glass of normal water. Of course, the dragon is stupid. |
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Title: Re: Easy: Knight and Dragon Post by grimbal on Apr 22nd, 2004, 3:30pm PS: assuming that the dragon is stupid leads to other silly solutions: The dragon did not realize that the glasses would be switched and brought clear water, while the knight brought water from well 1 because it was on the way to the duel arena. |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Apr 22nd, 2004, 3:42pm If you read through the whole thread (or it might be in one of the other threads for this puzzle), you will see that it has already been figured out how both the Knight and the Dragon can guarantee their own survival. So the fact that the Dragon dies indicates he wasn't the brightest of lights. |
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Title: Re: Easy: Knight and Dragon Post by kevincmann on Jul 31st, 2004, 2:38pm I think the solution is that the Knight drank some lower level water before the duel, therefore having the well 7 water cancel out the poison instead of being the poison. The dragon, otherwise, could not prepare in the same way because 7 is the highest. This is of course under a few assumptions, one being that the duel is an organized event in which they exchange water and sees who dies (which sounds silly). |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Aug 5th, 2004, 11:32am on 07/31/04 at 14:38:40, kevincmann wrote:
The dragon can prepare in the same way. He has access to all 7 wells, so he can drink from anyone of them. Somewhere in this thread or another for the same riddle, someone has stated what each must do to be assured of survival under all circumstances (that is, under all possible combinations of water from the 7 wells). This assumes that the amount of water drunk from the wells is not crucial: 1) Before the contest, the contestant (knight or dragon) drinks from well #1. 2) At the contest, he drinks the water brought by his opponent. If the water was from a higher numbered well, he is cured. If the water was either from well #1 or was ordinary water, he is still poisoned by well #1 water. 3) After the contest, he goes back to well 1 and drinks again. Now he is definitely poisoned by well #1 water. 4) He goes to any higher-numbered well and drinks, curing the poisoning. Since the dragon died, it is evident that he did not figure this out. That the knight lived either means that he followed this procedure or some variant, or was simply lucky enough that the dragon didn't bring water from well #1. |
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Title: Re: Easy: Knight and Dragon Post by colby wallace on Aug 20th, 2004, 6:54am You people are not getting the rules to the original actual riddle. Here's the real skinny on this: A dragon and a knight lived in a valley. In this valley there were six poison wells on the side of a mountain. The wells contained a very strange kind of poison. If you drank from a lower level well, you would die unless you drank from a higher-level well within two minutes after drinking.That is to say, if you drank from the first well, you could save yourself by drinking from the second, third, fourth, fifth, or sixth. If you drank from the fifth well, you could only survive by drinking from the sixth well. Both the knight and the dragon could get water from the first five wells, but only the dragon could get water from the sixth well because it was so high up. One day, the knight and the dragon got tired of sharing the valley and decided to have a duel. The rules of the duel: They would each bring two glasses of water and give one glass to the other. And then the other would have to drink it. Then they would the second glass, which they brought for themselves. On the day of the duel, the knight and the dragon met. They exchanged glasses and drank the water in the glasses. Then they drank the water in their second bottle. The dragon died and the knight lived. Why? The canonical answer forthcoming... |
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Title: Re: Easy: Knight and Dragon Post by colby wallace on Aug 20th, 2004, 7:16am The canonical answer. Oh, BTW, the only water available in the valley is from the poisoned wells. There is no other water. That's part of the rules. Here we go... Remember, there is no antedote for the top well's water. The top well's water is also the antedote for anything the the Knight could give to the dragon. So one would think... The dragon, thinking this, brings two glasses from the top well thinking, "I will give the knight something that has no antidote!" He is also thinking, "Whatever the Knight gives me, I have the antidote for!" So far, this is how most everyone thinks of this. It would appear that the Knight has no recourse... The Knight, preparing for this, drinks from well #1, or the lowest level well before the duel. He arrives at the duel already poisoned... he then drinks the *antidote* for what he already has in his system, the top well's water from the dragon. That's well and good, but what does he drink now? And what does he give to the dragon. Aaaah... glad you asked. Since there is no "pure" water, the Knight makes some, two glasses full of it, by getting two half glasses from well #1 (the lowest well) and then adding water from well #2 to each glass. He brings these two placebo concoctions to the duel. When he drinks from his own glass, he is fine. He also gives a placebo to the dragon, who then proceeds to drink from his own #6 (highest well) glass, thus poisoning himself in a way that has no antedote! Now, you may say that the dragon could double-cross- counter-think of this possibility and also poison himself before arriving, and then in response the Knight could... and the dragon could also, knowing what the Knight will probably do, bring #1 well water for the Knight to drink... You get the picture. There is no way to *insure* one's survival actually. In reality, it is an elaborate game of one upsmanship, not unlike the "odds/evens" game one played as a kid where you would put out 1 or 2 fingers simultaneously with a friend and if there are an odd number of total fingers, you win, evens you lose. Still, I have provided the canonical answer, flawed as it is. Good day to you all and have a happy. |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Aug 20th, 2004, 8:29am You might want to consider a few things, colby. 1) Your version of the riddle is not the same as that posted, and to which everyone has replied. If you change the riddle, you have no right to dismiss earlier comments for failing to conform to your version. 2) Even given the differences in the versions, the discussion on this riddle (which occurs in several threads, so some of what I am refering to may not be in this particular thread) has covered a significant number of variations, including yours. You will find that your "canonical solution" has already been given - including the creation of unpoisoned water from mixing the water of two wells. 3) The procedure I outlined in the post before yours still guarantees survival, provided the contestants bring the extra water with them to drink right before and after the contest, before they succomb to the poisoning (your version has to allow this, as your solution still requires the knight to poison himself before the contest begins). If you demand a match in the amount of water drunk from higher and lower-numbered well to exact a cure, then the contestent must judge how much water to drink by their condition. I.e. if the drink a glass of "curative" water, but are still poisoned, they know that the other must have given them well #1 water, and so they need another glass. If they can't accomplish this, then they would have died long ago, since only poisoned water is available to them. The only way the contestants can prevent such a ploy is to ensure each does not get away to go drink something else in the 2 minutes after the exchange. But if they are smart enough to recognize the need for this, why would they not also be smart enough to simply wait 2 minutes before exchanging the first glass. If the dragon did this, the poor knight would die from his pre-poisoning before the official duel began! |
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Title: Re: Easy: Knight and Dragon Post by rmsgrey on Aug 20th, 2004, 11:22am There's also the question of how mixing creates pure water - how can the water in a glass tell whether its well 1 water to which well 2 water has been added, or well 2 water to which well 1 water has been added? While I have proposed a mechanism whereby the water can tell in which order you drink it, by breaking down in your body, I can't think of a way for water stored in a glass to tell. Of course, if it's all magic, then of course it could work, but in that case you should mention explicitly that you can neutralise water by mixing it outside the body if that fact is important to the intended solution |
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Title: Re: Easy: Knight and Dragon Post by towr on Aug 21st, 2004, 5:53am on 08/20/04 at 11:22:19, rmsgrey wrote:
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Title: Re: Easy: Knight and Dragon Post by jmlyle on Aug 21st, 2004, 2:00pm on 08/20/04 at 06:54:24, colby wallace wrote:
Actually, I'm pretty certain that this is NOT the original riddle. I'm not sure what it says currently, but back when this forum formed, the riddle was: Quote:
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Title: Re: Easy: Knight and Dragon Post by rmsgrey on Aug 22nd, 2004, 7:55am on 08/20/04 at 11:22:19, rmsgrey wrote:
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Title: Re: Easy: Knight and Dragon Post by The Deacon on Mar 2nd, 2005, 1:54am I would have to agree with the solution where the knight drinks water beforehand, and brings a glass of plain water to the dragon. It does not say that there is a source of pure water... but then again it doesn't say there isn't. It just says that 7 poisoned wells EXIST. And the dragon and knight MUST have a source of regular pure water or else they would both have died a long time ago; it doesn't say that the two have to drink only from the wells daily. |
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Title: Re: Easy: Knight and Dragon Post by Krista on May 25th, 2005, 2:55pm OK. Here is my solution to the riddle in which the knight would live and the dragon would die. The knight drinks from well 1 before the duel. The dragon brings water from well 7 for the knight. The knight brings ocean water for the dragon. They switch glasses. The dragon drinks from well 7 to cure himself but dies instead. The knight survives because the well 7 water cured him. I think that the knight using the ocean water (neutral) is valid because it falls within the parameters of facts given in the riddle (they are on an ISLAND!) :P I wouldn't agree with the notion of the knight coming up with plain water out of nowhere. I like the idea of neutralizing Well 1 water with Well 2 water, however I'm not sure it would work. The only argument I would give with my solution is that the dragon may notice the distinct taste of the ocean water and not drink Well 7 water after. But hey, do dragons have a sense of taste? ;D |
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Title: Re: Easy: Knight and Dragon Post by alex suvorov on Jun 13th, 2005, 5:47pm Yes, it is an elegant solution because the problem assumes that the Knight is good and Dragon is evil. The Tom's answer totaly agrees with this assumtion. |
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Title: Re: Easy: Knight and Dragon Post by Deedlit on Jun 13th, 2005, 5:51pm I don't really see what good and evil have to do with it. If the knight doesn't want to kill the dragon, he shouldn't show up for the duel. |
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Title: Re: Easy: Knight and Dragon Post by n0ser on Jun 24th, 2005, 7:59pm has anyone sujested that the knight drank from a lower numbered well before the duel and when he drank the water that the dragon gave him it only neutralized the poision that he had already drank? |
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Title: Re: Easy: Knight and Dragon Post by paul schmitz on Jun 30th, 2005, 10:31am yes, they have. this is a decent riddle but if you allow for the dragon to be as smart as the knight, then there is no way to guarantee a solution because the dragon can do everything that the knight can do. i'd like to see the original riddle. ;D Here's an addition: assume that if you have been poisoned then there is only enough time to drink from one well before you will die. The problem with the original puzzle and my scenario is that there is no way to guarantee the solution. In other people's answers, the dragon could assume that the only way the knight thinks he can kill the dragon is to use pure water. Here, the dragon will drink nothing. On top of that, though, the knight could have thought of this scenario as well, and could have given him any water to kill him. |
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Title: Re: Easy: Knight and Dragon Post by qt31416 on Jun 30th, 2005, 12:40pm I don't see the point why most of you assumed that the dragon will get the water from well 7. assuming that the dragon knows how to count, then why in the world would he take the water from well #7. i still think that the riddle is lossely stated. and with some of the guys' arguments with mixing water from different wells... did you even think first if dragons ever existed? ;D |
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Title: Re: Easy: Knight and Dragon Post by paul schmitz on Jul 2nd, 2005, 12:07am most likely, the water is tainted and the knight is hallucinating. The entire story about different wells and poison cures is imaginary. The dragon is actually a moss-covered rock sitting near a cave. |
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Title: Re: Easy: Knight and Dragon Post by Jim Lane on Jul 2nd, 2005, 2:36am It can't be assumed that the knight and dragon have access to potable water, simply because they've survived until now. Perhaps they can gather and drink only a negligible amount of rain water, but the rain supports plants, and they get the moisture they need by eating the fruit. (Yes, I know that dragons aren't classically depicted as scarfing down peaches and getting the juice all over their snouts. They aren't classically depicted as using poisoned wells, either.) It can't even be assumed that they have access to ocean water. Perhaps the island's shore consists entirely of steep cliffs that the knight can't climb up or down. If the dragon flies down to the sea and tries to dip in a glass, the waves and the ocean spray get enough water on his body to cool him to the point where he can't maintain his magical internal fire, which is essential to dragon metabolism. Of course, it also can't be assumed that they don't have access to non-poisoned water. If the dragon's internal fire means that he could just try breathing fire on the knight, then probably the knight has a magic sword. In a duel of fiery breath against magic sword, each antagonist has a significant risk of being killed. Each judges his chance of survival to be better with the water duel. |
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Title: Re: Easy: Knight and Dragon Post by Deepak Agarwal on Jul 19th, 2005, 1:38am There are many solutions and assumptions. but I think the most appropriate answer is like this: The riddle says that "If you drink from a well, you can only save yourself by drinking from a higher numbered well". It does not says the highest numbered well. So I assume that its like if you drink from well 1 then you can save yourself by drinking from well 2 and so on. Now because only dragon could go to well 7 so he brings the water from well 6 as he thought that knight can never reach well 7 and would die. Now here is what happens in the duel: Before the duel knight drinks the poisoned water from the lowest well, well-1 and then brings the plain water to the duel (I assume it was available on the island otherwise how could they survive) (or perhaps he takes half of glass of water from well 1 and fill other half from well 2 which neutralizes the water) and dragon brings the water from well 6. The exchage the glasses. Knight gets cured with the water of well 6 and dragon run towards the well 7 and drinks the water of well 7. But as he was given plain water thus well 7 does not cure him rather poisoned him so he dies. Thus knight survives and dragon dies. Do you have any other concrete answer? |
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Title: Re: Easy: Knight and Dragon Post by SuperSaiyan on Sep 18th, 2005, 10:12am Behold! Both of them have a way of guaranteeing their 100% survival! Suppose we denote N to being at state N, i.e being poisoned from well N (N=0 means cured), and M(N) means drinking from well M when in state N (0(N) = N because drinking plain water does not change the state). Suppose that X is the unknown water that is brought to the duel. Knight's way of guaranteeing his survival: 2(1(X(1))) Drink from well 1 before the duel. Drink the water the dragon brought (now the knight is either cured or poisoned from well 1) Drink from well 1 again (now the knight is poisoned from well 1, for sure) Drink from a well numbered higher than 1, say 2, and be cured. Dragon's way of guaranteeing his survival: 7(1(X)) Drink the water the knight brought. Drink from well 1 (now the dragon is poisoned for sure). Drink from well 7 and be cured. (OR do what the knight did) If the dragon had numerous ways of guaranteeing his survival 100% and yet he died, the riddle is flawed, because in that case why one could say for example: "The dragon drank the water from well 1 that the knight brought him, and refused to cure himself afterwards since he acknowledged the knight's superiority." or: "as the dragon was raising the cup to his lips, the knight drew his sword and stabbed him!" hey, actually someone said that =) Stupid dragon. Screw him, that serves him right. |
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Title: Re: Easy: Knight and Dragon Post by Kayback on Oct 16th, 2005, 11:19am Honestly I'm no good at these things, but personally I think this one is flawed. It states "if you drink from a well, you can only save yourself by drinking from a higher numbered well" It doesn't clarify if this would act as an antidote, or kill you as well unless you got a higher number as well. Ad infinitum. I DO like the clear water one, and I support the taking the water that surrounds the island more than a mixing of the waters. KBK |
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Title: Re: Easy: Knight and Dragon Post by hereyago on Nov 29th, 2005, 12:06am This is how it works: The knight drinks from well #1. Then he brings a glass of well #1 water. And it is most likely that the dragon will bring #7. They switch glasses and the knight is cured and dragon is poisoned. They duel and dragon dies because the question does not state that they had time to go drink from another well between their glass drink and duel. |
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Title: Re: Easy: Knight and Dragon Post by hereyago on Nov 29th, 2005, 12:06am Or the knight can just SLAY THE FREAKING DRAGON during the duel. |
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Title: Re: Easy: Knight and Dragon Post by Josh Q on Nov 29th, 2005, 11:01pm Just wondering... why can't the dragon just bring water from well 1? How would the knight live, since he drank the water that the dragon gave him (or her, for you PC folks)? |
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Title: Re: Easy: Knight and Dragon Post by Three Hands on Nov 30th, 2005, 4:11pm I think SuperSaiyan summed up the solution best a few posts above. Try following through the working, and if you're still confused, ask again :) |
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Title: Re: Easy: Knight and Dragon Post by kimmy on Dec 21st, 2005, 11:02pm ok solved it the knight drinks from well 1 and brings normal water the dragon brings water from well 7. when the night drinks it it cures him of the poison from well1, then the dragon flies up to well 7 to cure himself of the poison he thinks he has ingested and it kills him |
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Title: Re: Easy: Knight and Dragon Post by Arrkhal on Dec 24th, 2005, 3:37am Quote:
Actually, in the supposedly original version, the dragon can insure his survival, while the knight cannot. If the dragon drinks from well 5 before the contest, and has his glass full of water #6, his survival is guaranteed. Nothing the knight can get is an antidote to water #5, so the second glass of water 6 will always be a cure. The knight, on the other hand, would only be able to guarantee survival if he uses a trick glass that has two compartments, or some other way to keep two different types of water seperate. Then he'd be able to pre-poison himself from well 1, drink what the dragon gives him, drink some more water #1, and then drink some water #2. Just like the solution for the 7-well version. But if he's stuck with a regular glass and can't somehow rig up a way to keep two waters seperate, it could go either way for him. |
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Title: Re: Easy: Knight and Dragon Post by Threeme2189 on Jun 12th, 2006, 6:43am asuming that the island they are both on is surrounded by non lethal but very salty sea water i think i might have a partial solution involving a smart knight and a less smart dragon. the knight drinks from well 1 and brings the dragon water from any well mixed with sea water. the dragon brings water from well 7. when they both drink each others water the knight is cured from his self poisoning and the dragon believes the knight wants him to poison himself with water from well 7 (that is incurable) and that the water the knight gave him is purely sea water so he drinks from no well after that and eventually dies. i don't think what i posted is 100% right but i do assume that they can use sea water because of the fact that they are on an island. |
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Title: Re: Easy: Knight and Dragon Post by kiochi on Dec 20th, 2006, 8:02am OK, so we know the dragon dies and the knight lives and we have to construct a scenario in which this will occur. I can think of two: one with a stupid dragon and a semi-clever knight, and one with a stupid knight and an insightful dragon: A) Knight brings water and pre-drinks a poison, then the dragon brings either 6 or 7, and drinks from 7 afterwards. B) The dragon expects scenario (A), so it brings water instead of a high-level poison. The stupid knight doesn't drink anything beforehand--just hopes for the best, and gives the dragon poison number 6 (the most powerful he has access to). After the duel, the dragon dies of the poison it thought was water, while the knight will do fine without drinking anything. In either case we get the outcome we were told to explain. |
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Title: Re: Easy: Knight and Dragon Post by Icarus on Dec 20th, 2006, 6:21pm I wouldn't call the dragon very insightful for your second scenario, either. If he were insightful, he would have realized how to ensure his own life, and given a better chance poisoning the knight. Either one can save themselves by the following strategy: Drink from #1 beforehand, Drink from #1 again afterwards, then Drink from any higher numbered well. The first drink means they are poisoned by #1. If their opponent brings higher-well water, it will cure them, then they repoison themselves and cure themselves once again. On the other hand, if their opponent brings either plain water or more well #1 water, they are not cured, and the third dose makes no change. The fourth dosing, with higher-well water, cures it all. Since the dragon dies, we know he did not do this. So he wasn't insightful enough. Since the knight lives, he was either insightful, or lucky. (And as for what the dragon should have brought - I suggest well #1 water. At least this way the knight is poisoned, and it is just as likely to be successful against any strategy of the knight's as ordinary water is.) |
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Title: Re: Easy: Knight and Dragon Post by simonu on Oct 12th, 2009, 6:25pm they are on an island. the knight brings water from the sea and drinks water from well 1 before meeting the dragon. the dragon either brings water from number 6 or number 7 (being higher wells than those unreachable for the knight) or sea water. The drinking for the knight neutralizes the poison. after drinking the dragon's water, he drinks again from well 1 and after from well 2. If the dragon brought him sea water, he would just have taken a bit more of well 1 water, neutralized by the drinking of well 2 water. if the dragon brought well 6 or 7 water, that would neutralize the first well 1 water. the further drinking would auto-counter. the dragon does not know what he is drinking. he might receive sea water or poisoned water. if he received poisoned water, he has to drink from well 7 afterwards, if he received sea water, the drinking kills him. so he cannot be sure whether to drink or not, and will have 50% probability, unless he drinks something before, as the knight did. |
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Title: Re: Easy: Knight and Dragon Post by ajfirecracker on Jul 17th, 2010, 5:10pm There are only two explanations for this: A) The dragon has every option available to the knight, plus the option of bringing/drinking well 7 water. The knight must be smarter/better at logic than the dragon to win, since any winning strategy he uses the dragon could simply copy and make a draw. There is no logical explanation for why the knight wins. B) The dragon has every option available to the knight, plus the option of bringing/drinking well 7 water. The fact that the dragon can access well 7 and the knight cannot is somehow dooming to him. Given our current set of assumptions, this cannot be the case, as the pattern 1-opponent's water-1-2 beats any choice for opponent's water. Therefore this pattern must not be allowed, or the puzzle is broken. The best way to disallow this would be to add a provision that drinking the same poison twice in a row is fatal (presumably, drinking a lesser poison after a greater one would also be fatal). That is, 1-seawater-1-2 is fatal because 1-seawater-1 is fatal. However, it's still the case that the dragon has every option that the knight has, and then some. All the provision does is take the game from "Draw, no one dies" to "One or both die at random". While random death certainly explains the knight living and the dragon dying, it's not very satisfactory as a puzzle solution. |
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Title: Re: Easy: Knight and Dragon Post by riddler358 on Apr 24th, 2016, 6:37am knight brings lvl 2 water and drinks exactly half of it right in front of dragon eyes so he can see it, he proposes a draw but dragon doesn't believe him he drinks only water he recieved from knight, knight drinks half of water recieved from dragon when he starts feeling sick, and the dragon even when dying in pain refuses to drink rest of water he brought, this is one very stupid dragon if he dies, and with some serious trust issues |
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