06-14-2010, 08:03 PM
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#9
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Wizard
Posts: 2,782
Karma: 29028512
Join Date: May 2010
Location: Florida
Device: Sony PRS 600, Nook ST, Toshiba Excite 10.1 AT 300
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Quote:
Originally Posted by omk3
Pdurrant, I'm enjoying your puzzles very much 
Spoiler:
Let's see now.
I have twelve coins, so I can divide them into 4 groups of 3, A, B, C and D.
I put A and B on the scales.
If they don't have the same weight, the fake coin is in either A or B.
If they do, the fake coin is in either C or D.
If the fake coin is in either A or B, I weigh A with C.
If they have the same weight, the fake coin is in B.
If they don't have the same weight, the fake coin is in A.
If the fake coin is in either C or D, I weigh A with C again.
If they have the same weight, the fake coin is in D.
If they don't have the same weight, the fake coin is in C.
I have now identified a group of 3 coins, one of which is the fake one. I give all three to the miser, and he can work out for himself which one is the fake one and throw it away, he still gets 2 good coins for my use of the scales.
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Way to go!
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