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        riddles >> easy >> Two condoms, three women
        
(Message started by: algorhythm on Oct 19th, 2005, 12:28pm)
Title: Two condoms, three women
Post by algorhythm on Oct 19th, 2005, 12:28pm
Searching through the archives for "condom" and "condoms", I'm not finding a solution to this problem. The only attempt to solve it I can find (except for Dr. Whiteys hilarious solution to the Monty Hall problem, here (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_easy;action=display;num=1028741912;start=35#35)) is TenaliRamans solution in this thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_easy;action=display;num=1054543296;start=9#9). His solution:

[hideb]For First Woman,
Put on both the condoms
For second,
Remove the top condom
For the third,
Take the condom which was removed earlier,turn it inside out and put in on again. [/hideb]

This is obviously wrong because [hide]Willywutang would then risk getting possible STD:s from the first woman,  also turning used condoms inside out for re-use sounds rather difficult.[/hide]

The only answer I can think of is [hide]that "sex" doesn't have to imply penetration.[/hide]

Is there another solution?

(There probably is a thread about this already, at least Icarus seem to be saying so in the TenaliRaman thread. Yet I'm not finding it - sorry if it's something I'm missing with the search functionality...)
Title: Re: Two condoms, three women
Post by towr on Oct 19th, 2005, 1:08pm
'Obvious' is quite possibly one of the most dangerous words when dealing with puzzles.

TenaliRaman's solution is correct. [hide]Remember Willy still has the other condom round his willy when he puts the second one back on inside-out.[/hide]


here (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_easy;action=display;num=1027805879;) is an earlier thread btw.
Title: Re: Two condoms, three women
Post by algorhythm on Oct 19th, 2005, 3:39pm

Quote:
'Obvious' is quite possibly one of the most dangerous words when dealing with puzzles.


Obviously! :) Thanks, didn't think that far. My apologies to TenaliRaman.

I did figure out why I didn't find that older thread myself ([hide]Max Age[/hide]). Man, am I supposed to read everything?? :) And think and stuff?
Title: Re: Two condoms, three women
Post by Icarus on Oct 19th, 2005, 6:05pm
All of us have had difficulties with the search function when we first used it. Quite frankly, I still have a lot of trouble with it when finding threads for which I remember significant details. So it is hardly surprising that someone unfamiliar with it, and who is searching for a thread he has no prior knowledge of, would not be able to find it.
Title: Re: Two condoms, three women
Post by Grimbal on Oct 20th, 2005, 2:29am
There is also the 2 men and 2 women variation.  2 condoms are enough.

But I am still not sure how many condoms are necessary for a 3 men and 3 women party.
Title: Re: Two condoms, three women
Post by Komninos on Oct 20th, 2005, 8:06am
Man that thread on the condom puzzle is hillarious!
The only thread I laughed harder with was the one with the mention of how long an orgasm lasts for a pig (among other things but that stuck to my memory for some reason along with the comments made about it).

This condom business kind of reminds me of an Asian puzzle "Towers of Hanoi" :-p
Title: Re: Two condoms, three women
Post by Guest on Oct 22nd, 2005, 11:22pm
wear one for first woman, the other for second woman, and for the third wear both and turn the outer one inside out
Title: Re: Two condoms, three women
Post by Icarus on Oct 23rd, 2005, 11:32am
And then he should start saving up for the paternity lawsuit that third gal is going to be bringing, as his semen from the first or second act is going to be on the exposed surface of the outer condom.
Title: Re: Two condoms, three women
Post by Komninos on Oct 23rd, 2005, 11:30pm
Willywutang would like to have safe sex with three women, any of whom may be carrying an STD. Given two condoms, how can he do so, while ensuring that no STD is passed from one woman (or possibly himself) to another (or to himself)?

Well last time I checked a fetus/pregnancy was not considered an STD, but you do have a point.
The riddle asks in the end that no STD is passed, but it mentions safe sex earlier so that should include no unwanted offspring too.
Title: Re: Two condoms, three women
Post by Grimbal on Oct 24th, 2005, 1:13am
And the women must be protected from the man's possible STD.  It would certainly be necessary with this kind of sex life.
Title: Re: Two condoms, three women
Post by percentdecimal on Oct 27th, 2005, 6:55pm
[hideb]
both for the first woman
flip the outside one for the second woman
then just the inside one for the third

rinse out the inside of the inside condom between "passes", if necessary  ;D
[/hideb]

This way no person touches a surface that somebody else touched.

And if you think about it, there are only four surfaces total (two sides to each condom), so this has to be the only way.
Title: Re: Two condoms, three women
Post by BNC on Oct 27th, 2005, 10:46pm

on 10/27/05 at 18:55:25, percentdecimal wrote:
[hideb]
both for the first woman
flip the outside one for the second woman
then just the inside one for the third

rinse out the inside of the inside condom between "passes", if necessary  ;D
[/hideb]

This way no person touches a surface that somebody else touched.

And if you think about it, there are only four surfaces total (two sides to each condom), so this has to be the only way.


Wouldn't work.
After the 2nd woman, all 4 surfaces are contaminated (the outside surface of the inside condom is in contact with the surface of the outside condom that was in touch with the 1st woman).

But you're on the right track -- all you need in a minor change.
Title: Re: Two condoms, three women
Post by DewiMorgan on Jun 6th, 2006, 4:41pm
[hide]1) Wear 2 layers
2) remove the outer
3) replace the outer, reversed[/hide]
Title: Re: Two condoms, three women
Post by Lozboz on Jun 20th, 2006, 3:08am
Pregnancy is not necessarily a problem; Firstly the riddle doesn't mention it, it's only talking about STDs. Secondly i doesn't say he 'really enjoyed' any of the 'encounters'. He may have been too tired/exhausted after the first to produce the baby-making material for the second/third.(On the other hand maybe not.)
Title: Re: Two condoms, three women
Post by Ither on Jul 14th, 2006, 4:17am
Easy,

[hideb]he puts on two condoms with the first, takes off the top condom with the second, and on the third he uses the top condom he had removed earlier and turns it inside out on top of the condom he'd been wearing the whole time.[/hideb]The first guy was close.
Title: Re: Two condoms, three women
Post by Icarus on Jul 15th, 2006, 7:32pm
Please note that this is exactly the solution TenaliRamen is quoted as giving in another thread. Also the link towr provides leads to an earlier thread that also contains the correct answer.
Title: Re: Two condoms, three women
Post by showmydog on Jul 22nd, 2006, 5:36am
TenaliRamans is exactly right
[hide]Two for the first
The inside one for the second.
With the inside one still on, put the otside one back on, inside out.
[/hide]

note: the inside one remains on at all times, and therefore Icarus was incorrect in saying:


Quote:
And then he should start saving up for the paternity lawsuit that third gal is going to be bringing, as his semen from the first or second act is going to be on the exposed surface of the outer condom.


no pregnancy would occur as the seme from all three performances is trapped in the inside condom

matt
Title: Re: Two condoms, three women
Post by BNC on Jul 22nd, 2006, 6:49am

on 07/22/06 at 05:36:46, showmydog wrote:
TenaliRamans is exactly right
[hide]Two for the first
The inside one for the second.
With the inside one still on, put the otside one back on, inside out.
[/hide]

note: the inside one remains on at all times, and therefore Icarus was incorrect in saying:


no pregnancy would occur as the seme from all three performances is trapped in the inside condom

matt


What do you mean "therefore..."?
Icarus was responding to Guest's post stating

Quote:
wear one for first woman, the other for second woman, and for the third wear both and turn the outer one inside out

and not to TenaliRamans's
Title: Re: Two condoms, three women
Post by kick on May 15th, 2007, 11:21am
sorry but this riddle could be solved an entirely different way -

The way the question is ambiguously written makes only one answer correct.  A person can always contract an std that is spread "skin to skin" - condoms can't protect against these kind of std's.  An example is HPV.  So the way the question is written makes the only possible answer 0 or he can't make sure he's safe....  Because 18 condoms couldn't protect someone against ALL stds.  It really depends what kind of std's one is talking about.
Title: Re: Two condoms, three women
Post by Bandy on Apr 14th, 2008, 4:38pm
Start by wearing both condoms. Have sex. Remove outer condom. Have sex. Now turn the outer condom inside out and wear it over the inner condom. Have Sex.
Title: Re: Two condoms, three women
Post by JiNbOtAk on Apr 14th, 2008, 8:06pm
One starts to wonder how cheap Willy is when he is willing to use the same condom for 3 times. Unless, he didn't orgasm at all, which might explain his attractiveness to the ladies.  :P
Title: Re: Two condoms, three women
Post by Sir Col on Apr 14th, 2008, 11:45pm

on 04/14/08 at 16:38:41, Bandy wrote:
Start by wearing both condoms. Have sex. Remove outer condom. Have sex. Now turn the outer condom inside out and wear it over the inner condom. Have Sex.

Hey, I think Bandy got it!  ::)
Title: Re: Two condoms, three women
Post by fizyka on Oct 1st, 2011, 4:56am
This is pretty good damn funny riddle;p
But in real life that wouldn't work, when Yu wear two condoms one on the top can easily move down or break because of friction....
Title: Re: Two condoms, three women
Post by Grimbal on Oct 1st, 2011, 2:56pm
A true mathematician can wear any finite number* of condoms.   ::)

* positive or zero integers.  Wearing a fractional or imaginary number is left as an exercise to the reader.
Title: Re: Two condoms, three women
Post by ThudnBlunder on Oct 1st, 2011, 6:05pm
It is rumoured that Houdini started early when his bastard older brother obtained his revenge by employing a pin on his(?) father's condoms.
Title: Re: Two condoms, three women
Post by mirela on Apr 27th, 2012, 11:44am
1st women:Put the second condom over the first.
2nd women:remove the first condom
3rd women: reverse the first one
Title: Re: Two condoms, three women
Post by traughb on Jul 11th, 2012, 5:56pm
Double bag it and have a foursome.
Title: Re: Two condoms, three women
Post by manish682 on Dec 17th, 2012, 3:12am
Two condoms & three women, quite possible if the third woman is your wife, you don't need one with her. ;D
Title: Re: Two condoms, three women
Post by cartoonle on Dec 18th, 2012, 5:06am
This riddle starts without puzzle text? I can't find it ...
Title: Re: Two condoms, three women
Post by Grimbal on Dec 18th, 2012, 8:07am
At the top of the page is a big question mark and the words "RIDDLES SITE" in red.  Click on it.
Then click on the category "easy" and search "CONDOM".  (it's 25% down the page)
Title: Re: Two condoms, three women
Post by marlonmark on Jan 2nd, 2013, 1:19am
I totally agree with Ither as even i had the same thought.
Title: Re: Two condoms, three women
Post by rloginunix on Oct 28th, 2013, 9:22pm
In my articles where I preach that it's not the what (answer) but the how is important I claim that there is a finite number of Basic Approaches that work across any and all the hard science disciplines from quantum mechanics to differential geometry and everything in between. So far I've identified 8 - Division, Elimination, Equation, Rearrangement, Scope Expansion, Scope Reduction, Space Time, Substitution.

This particular problem and many others like it are solved using the Space Time Basic Approach:
Test which one of the only four possible space-time combinations of events and/or objects listed below is useful:
1). Same space, same time.
2). Same space, different time.
3). Different space, same time.
4). Different space, different time.

Once armed with that knowledge one can quickly conclude that it's choice number 1) that works. Both condoms must occupy the same space at the same time. After the first intercourse only one condom is removed. After the second - there is a conflict. Resolve it using the same Space Time choice 1) but turn the removed condom inside out for the third intercourse.

This is an old peasant/wolf/goat/cabbage/boat problem in disguise. That problem is also solved using the Space Time Basic Approach. Other problems like it involve soldiers or husbands and wives crossing the river.

This problem can be reworded thus: how can each of two males have an intercourse with each of two females if only two condoms are available? The solution of course is the same except that the condoms are used in reverse order - male 1 has an intercourse with female 1 and after gives the outer condom to male 2 who has an intercourse with female 1. Male 1 has an intercourse with female 2 and after gives the condom to male 2 who, armed with the knowledge of the Space Time Approach, bravely puts the formerly inner condom over the originally outer one and has an intercourse with female 2. No need to turn anything inside out this time.

Incidentally the Russian Matryoshka Dolls use the same space/same time principle.
Title: Re: Two condoms, three women
Post by rloginunix on Nov 18th, 2013, 9:46pm
Taking a break from the coin puzzles I realized that the above problem can also be reworded thus: three males, one female, two condoms. Solution is again the same. But this time I applied a tiny bit of formalism.

M = {M1, M2, M3} are males.
F = {F1, F2, F3} are females.
S = {S1i, S1o, S2i, S2o} are condom surfaces, i = inner, o = outer.

1). One male, three females solution:
M1 S1i S2o F1
M1 S1i S1o F2
M1 S1i S2i F3

2). Two males, two females:
M1 S1i S2o F1
M1 S1i S1o F2
M2 S2i S2o F1
M2 S2i S1o F2

3). Three males, one female:
M1 S1i S2o F1
M2 S2i S2o F1
M3 S1o S20 F1
Title: Re: Two condoms, three women
Post by Grimbal on Nov 20th, 2013, 7:47am
Your formalism doesn't show the potential problem of condom-to-condom contact.  A dirty side of a condom can touch a clean side of another condom and contaminate it.
Title: Re: Two condoms, three women
Post by rloginunix on Nov 20th, 2013, 7:52pm
I was pondering the hourglass problem when I've read your reply, Grimbal.

This is my seventh or eighth problem solving experiment and the short of it is that it's still remains unclear to me where does the new come from?

After I've tried 7+7+11 and 11+7 it became obvious that it's not gonna work. Next, flip them both at the same time. After the 7m HG is done there will be 4 minutes left in the 11m HG. So what? The clock is ticking, right? 7 minutes went by. How can I use these 4 minutes? It would be nice to freeze them and replay them twice in a row. 7+4+4=15.

When I ran into this wall the time was ripe to reread the problem and reexamine what's given word by word. I'm no English major but the word "time" in "accurately Time 15 minutes" caught my attention.

Drawing on my past college experience what does it mean to "accurately time" something? This is a fascinating subject to itself. In theoretical physics they measure time in space. One second of time equals the amount of space covered by the ray of light given the opportunity to travel for this one second, three hundred thousand kilometers roughly.

Another way to measure time is to bounce a particle of light, a photon, between two mirrors. But in our much simpler case it's just some time interval between me saying "Start!" and then some time later saying "Stop!". That's the key to solving this problem. I figure it is puzzling at first for most people because we instinctively and quickly fuse two separate events - flipping the hourglass and starting the timer - together. Stepping on a land mine, body parts flying...

All we have to do to solve this puzzle is to separate in time these two events, let enough sand flow by until an opportune moment arrives and only then start the timer. So the solution is:

1). Flip both hourglasses.
2). Let the 7m HG run out.
3). "Start!" timing the 15-minute interval.
4). When the only 4 minutes worth of sand remaining in the 11m HG flow out flip it again.
5). Let these 11 minutes go by.
6). "Stop!" timing.
7). 4 + 11 = 15.

Sorry, now back to this.

[edit]
Forgot to explicitly qualify the approach that solves this problem. So for documentation purposes here it is - space time, choice number two - same space, different time.
[/edit]
Title: Re: Two condoms, three women
Post by rloginunix on Nov 20th, 2013, 8:17pm
You are absolutely right, Grimbal. I noticed as much myself when I was posting the answer. When I was running through the indices for S I felt that something is wrong. Not only that. My notation also doesn't make it obvious that two condoms must at some point occupy the same space at the same time.

Here I hope is an improvement. So Ms and Fs remain the same. The surface get's an extra qualifier c for clean, d for dirty. Same qualities are allowed - cc, dd - are OK, crossing the beams is not allowed ("crossing the beams" is a humorous remark from Ghostbusters).

Before a surface can be bonded to a person it must carry the "c" quality. All the surfaces are initially Clean. Once such connection is established it must stay permanent for the duration of the experiment.

I'm also adding the notation to reflect the fact that two condoms may occupy the same space at the same time.

1). 1 Male, 3 Females:

(M1 S1id) S1oc S2ic (S2od F1)
(M1 S1id) (S1od F2)
(M1 S1id) S1od S2od (S2id F3)

2). 2 Males, 2 Females:

(M1 S1id) S1oc S2ic (S2od F1)
(M1 S1id) (S1od F2)
(M2 S2id) (S2od F1)
(M2 S2id) S2od S1id (S1od F2)

3). 3 Males, 1 Female:

(M1 S1id) S1oc S2ic (S2od F1)
(M2 S2id) (S2od F1)
(M3 S1od) S1id S2id (S2od F1)

I'm wondering now if formalizing the puzzle/riddle right off the bat will help solving it quicker?
Title: Re: Two condoms, three women
Post by rmsgrey on Nov 21st, 2013, 4:47am

on 11/20/13 at 20:17:21, rloginunix wrote:
I'm wondering now if formalizing the puzzle/riddle right off the bat will help solving it quicker?

In general, using a good formalisation will help with solving a problem more quickly, but using a poor formalisation won't.

One of the skills of puzzle solving is the ability to find good formalisations quickly - which often involves having some idea of what the solution should look like.
Title: Re: Two condoms, three women
Post by rloginunix on Nov 23rd, 2013, 11:48am
Yes, rmsgrey. The chicken or the egg problem. I've been puzzling over this on and off for the past several months.

In programmer's wishful thinking if there only existed a purely mechanical procedure into which in goes the riddle/puzzle/problem and a finite amount of steps and a finite amount of time later, preferably while we're still young, without human involvement out comes the answer "Nah, no solution here" or "Yeah, use formalism so and so to find at least one solution".

But if memory serves me right, Alan Turing and Kurt Godel gave a resounding no can do on this one. Which means riddles and puzzles can still riddle and puzzle us. And something very not logical like intuition or hunch must be employed to find a solution.
Title: Re: Two condoms, three women
Post by Grimbal on Nov 23rd, 2013, 1:04pm
It is not because some problems cannot be solved formally that formalism is useless for all problems.

I think what helps solving a problem fast is to find the essence of a problem.  If that essence can be described formally (it could be a set of equations), you can use all the tools you know to solve it.
Title: Re: Two condoms, three women
Post by rloginunix on Nov 24th, 2013, 8:37pm
Fully agreed. And by no means my intention was to imply that formalism is useless. Of course it's useful.

Don't want to pollute this thread with an off topic discussion but what I meant is that if we take Godel's and Turing's findings at their face value - a universal problem solver doesn't exist - then my interpretation is that finding a solution to a riddle/puzzle/problem takes two mutually exclusive skills - pure logic (formalism) and pure not logic - call it intuition, gut feeling, hunch, imagination or grasping of what you call the essence.

A little bit of the latter at first and likely lots of the former next. That's all.

Not sure if it deserves a separate thread. Probably not. There's one already out there - "general problem-solving/whatever"/"how to become better at problem-solving/riddles".

As a side remark don't see people sharing their solution paths. Is that frowned upon around here?
Title: Re: Two condoms, three women
Post by rmsgrey on Nov 25th, 2013, 7:22am

on 11/24/13 at 20:37:31, rloginunix wrote:
As a side remark don't see people sharing their solution paths. Is that frowned upon around here?


How much people share depends on the problem - a "riddle" where you either see the answer, or don't, there's often no solution path to share.

For puzzles here in easy, the more experienced posters will often post cryptic hints to make it clear that they're aware of the (intended) solution, or deliberately post unintended solutions in order to avoid the situation where someone who hasn't seen that problem (or a variant) before comes across it, then the first three posts are three different uberpuzzlers giving complete solutions...

And, of course, even when a completesolution is given, it's often posted as a finished product - the result of the poster's reflections on the problem rather than a record of them.

On the other hand, there are problems, particularly in the hard forum, where people have posted partial solutions or thoughts about possible solutions, and a communal solution path has been recorded.
Title: Re: Two condoms, three women
Post by Grimbal on Nov 25th, 2013, 8:24am
The banner on the main page says:
"explaining how you arrived at an answer is more valuable than the answer itself"
So it is actually encouraged.  Especially on the harder problems.  An Uberpuzzler would never admit he actually had to think on the easy problems. ::)
Title: Re: Two condoms, three women
Post by rloginunix on Nov 26th, 2013, 1:59pm
Aah, I see. Egos and ambitions. Good stuff, good stuff. Not my cup of tea I'm afraid. Before I found this forum my idea was of an academically oriented place where approaches and problems are linked together. Here are all the problems that this approach solves. And here are all the approaches that solve this problem. Wikipedia of sort with a rather narrow band of material type - classification of solution types. Solvepedia or some such. This forum is of much different flavor and format. And of course when in Rome do what Romans do.

Last question if I may. What is the official take on the already solved problems?

Sorry, fat fingered something on the keyboard and the site did the post before I finished typing.

Anyway, if I read the problem, go away, solve it, then come back but someone has posted a solution. Is it OK if I post mine or is it best to just shut up and move on?
Title: Re: Two condoms, three women
Post by towr on Nov 26th, 2013, 10:49pm
I'd say that depends on a few things.
If the topic was recent I find even a "dammit, you just beat me to it" acceptable enough (You'll also see a lot of posts that were edited just to add that to the top, because sometimes someone beats you to it while you're writing a reply).  
If it's been a while (for me) it becomes a question of whether a reply adds anything, like a different solution method, a generalization etc. So if there have only been answers, but no solution path, then posting one would contribute something. If there's already a solution but you have an easier/clearer one, or a shorter one, or even an alternate one that is just interesting, that also adds something worthwhile.
When it comes down to it though, unless you resurrect a dozen topics per day no one is likely to be bothered.
Title: Re: Two condoms, three women
Post by rloginunix on Nov 27th, 2013, 5:55pm
Got it, makes sense, thanks for being patient with me.

Happy Thanksgiving!
Title: Re: Two condoms, three women
Post by rmsgrey on Nov 28th, 2013, 9:31am
In addition to the "edit: must type faster" posts and the "here's a (better/different) solution" posts towr mentions, there are:

* Okay, the intended answer's been found, but if you read the question carefully, it doesn't rule out this one (sometimes known as "thinking outside the box")

* That problem's been solved, but how about this related one? (sometimes the variant ends up taking over the thread)

If a problem's been solved a while, then posting just to say "I solved this too" (even if you give a complete solution) is more annoying than edifying for other people - unless you also add something new to the thread (besides your name).

The other point of etiquette towr touched upon is that there's no rush to post everything at once - sure, people get excited the first time they come across somewhere like this, and their first instinct is to dive in and post wherever they have anything to say, but it's better to pace yourself - you'll get more attention for each of your posts that way, and whatever conversation was going on when you arrived can continue without suddenly being buried on page three...
Title: Re: Two condoms, three women
Post by rloginunix on Nov 28th, 2013, 3:20pm
Point taken. Quality over quantity. Sniper shots over loose cannon fire. Must have something new to say.

My only observation is that in the forum's search functionality it would be nice to inhale all the puzzles but output only those that are still pending:

select * from puzzles where solved = false

or some such.
Title: Re: Two condoms, three women
Post by alien2 on Apr 13th, 2014, 1:35pm
One of three women is your wife and you don't want to sleep with her.  

Or one woman is a virgin.  


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