コイン計量ゲーム

(オリジナル) Coin Weighing Game

I think that about 25% of the time there is no "fake" coin. Either that or the weight differential is so small as to be negligible with lots of coins on the scale.

(オリジナル) Upon further review - I'm just not that good at the game.

(オリジナル) We've posted an update.

This should
1) solve the problem you mentioned
2) ensure that the game will be lost if a wrong move is made
3) make the result more random if a correct move is made

(オリジナル) I AGREE with DingleBerries, even though this message is from 2006.

(オリジナル) In 39 coins, there are initially 78 possibilities (one of 39 coins is either heavier or lighter). @Everyone You must make sure that the first weigh splits the possibilities into no more than 27 each in cases of weigh result being <, =, or >. Then @Everyone you must make sure that the second weigh splits the possibilities into no more than 9 each in cases of weigh result being <, =, or >. Then again, @Everyone you must make sure that the third weigh splits the possibilities into no more than 3 each in cases of weigh result being <, =, or >. Then finally, @Everyone, you must make sure that the fourth weigh splits the possibilities into no more than 1 each in cases of weigh result being <, =, or >. And after it's been narrowed down then you can pick the answer.