CRe Posted October 28, 2009 Report Posted October 28, 2009 Chambahs and root if you can't post without flaming each other don't post at all.
rootbear75 Posted November 1, 2009 Report Posted November 1, 2009 The False Coin You are given 18 coins but you find out that one of the coins (you don't know which) is fake and weighs less than any of the others. How can you be able to detect the false coin using nothing but a normal balance scale only three times?
Samapico Posted November 2, 2009 Report Posted November 2, 2009 The False Coin You are given 18 coins but you find out that one of the coins (you don't know which) is fake and weighs less than any of the others. How can you be able to detect the false coin using nothing but a normal balance scale only three times? 1) Compare 2 stacks of 6 coins from the 18 coins If set A > B, keep set A; if B > A, keep set B, if A = B, keep the 6 coins you did not weigh. 2) Compare 2 stacks of 2 coins from the 6 coins you kept If set A > B, keep set A; if B > A, keep set B, if A = B, keep the 2 coins you did not weigh. 3) Compare the 2 coins you kept Whichever weighs less is the false one
Chambahs Posted November 2, 2009 Report Posted November 2, 2009 (edited) Weigh the first 6 and hope you get lucky. Edited November 2, 2009 by Chambahs
rootbear75 Posted November 3, 2009 Report Posted November 3, 2009 Sama +1... I'll post another when i get home tonight.
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