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Topic: Water Buckets (Read 1468 times) |
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Mixster
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Fill the 5 gallon bucket and use it to fill the 3 gallon bucket (leaving 2 gallons in the 5 gallon bucket.). Empty the 3 gallon bucket and pour the 2 gallons from the 5 gallon bucket into the 3. Again fill the five gallon bucket. Top off the 3 gallon bucket (using up 1 gallon of water). You'll be left with four gallons in the five gallon bucket.
-Mixster
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| « Last Edit: Nov 19th, 2002, 5:46pm by william wu » |
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Tony
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Re: Medium: Water Buckets
« Reply #1 on: Jul 25th, 2002, 9:24am » |
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You can do it another way:
Fill the 3g bucket, pour it into the 5g bucket. Fill the 3g bucket again, pour as much as you can into the 5g bucket. This leaves you with 1g left in the 3g bucket, and the 5g bucket full. Dump out the 5g bucket, and pour the 1g of water from the 3g bucket into the 5g one. Now fill the 3g bucket again, and pour the whole thing into the 5g bucket.
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otter
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Re: Medium: Water Buckets
« Reply #2 on: Aug 9th, 2002, 7:29am » |
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Actually, there may be another way. IF the buckets are uniform in shape (e.g. cylindrical), fill each bucket. Slowly tip the five gallon bucket, emptying it until the water level simultaneously touches both the lip of the bucket opening and the point where the bucket bottom meets the wall of the bucket. The 5 gallon cylinder will now be half full (2.5 gallons). Do the same with the 3 gallon bucket (1.5 gallons at half-full). 2.5 gallons + 1.5 gallons = 4 gallons.
The original answer is more elegant and covers a larger universe of container types, but this solution would work for this special case.
For those who are interested, this was the puzzle presented to John McClain (Bruce Willis) and Zeus (Samuel L. Jackson) in "Die Hard with a Vengence". 
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GRAND_ADMRL_THUORN
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Re: Medium: Water Buckets
« Reply #3 on: Oct 29th, 2002, 8:52pm » |
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this question should probably be dropped down to easy
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tigermeat
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Re: Water Buckets
« Reply #5 on: Dec 6th, 2002, 2:45pm » |
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there's at least one more solution - fill up the 5 gallon, then fill up the 3 gallon. empty the 3 gallon, and pour the remaining 2 gallons from the 5 gallon into the 3 gallon. then, fill up the 5 gallon again. this is where it gets different: immerse the 3 gallon into the 5 gallon, until the top of the 3 gallon is flush with the top of the 5 gallon. the amount displaced should be 3 gallons, and 2 gallons should be left behind.
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jon_G
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Re: Water Buckets
« Reply #6 on: Dec 8th, 2002, 6:37pm » |
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I came up with the first answer in about a minute. It should be put in easy.
Wouldn't imersing the other bucket into the five gallon bucket make some water spill out thus not accuratly measuring four gallons.oh I see my error I guess from the 2g left in the 5g bucket you could just empty the 2g in the 3g bucket. My eyes have been opened thanks. 
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| « Last Edit: Dec 10th, 2002, 11:01am by jon_G » |
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redPEPPER
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Re: Water Buckets
« Reply #7 on: Dec 17th, 2002, 1:21pm » |
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There's a problem with the immersion of the 3 g bucket in the other bucket. First we have to assume that the big bucket's opening is wide enough. I think solutions are less elegant if they rely on assumptions that are not necessary.
More problematic is: what about the thickness of the 3 g bucket? The displaced volume when immerged can't be the same as the inside volume of the bucket.
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rmsgrey
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Re: Water Buckets
« Reply #8 on: Apr 14th, 2003, 12:36pm » |
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In any case, the infinite supply of water seems rather wasteful - without any immersion/flotation tricks, the original solution uses 10 gallons - of which 3 get dumped, 3 end up in the small bucket and 4 in the large. The other solution listed used only 9 gallons, but dumped 5 leaving the small bucket empty.
Which of the two solutions is most water efficient depends on whether you can keep the 3 gallons spare at the end of the first solution. Also if you had a limit to supply of between 9 and 10 gallons, you can force one solution over the other.
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mike strong
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the other answer about tipping the bucket so that its half full. That couldnt be an exact measurement. Such as in the movie die hard, they needed the water measurement to be exact in order to disarm the bomb. 
Strong.....OUT!
F ryan seacrest
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