Find the Fake Coin: Weighing Strategy with 27 Coins in 3 Attempts

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To identify the fake coin among 27 coins using a balance scale in just three attempts, first divide the coins into three groups of nine and weigh two of the groups. The lighter group contains the fake coin. Next, take the lighter group and divide it into three groups of three coins and weigh two of those groups. The lighter group will again contain the fake coin, leaving you with three coins. Finally, weigh any two of the remaining coins to find the lighter, fake coin. This method efficiently narrows down the possibilities within the constraints given.
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Can someone help me please? This is urgent

I can seem to figure this question out. I'm always left with 4 coins and 1 try.

Using a simple balance, could you (by weighing) find the one fake (lighter) coin in a group of 27 coins. Here's the catch...you may only weigh the coins 3 times. You may not use anything else. How could this be accomplished?

If you can get the answer as fast as possible that would help. Thanks.
 
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I know that someone has already done this but i can't seem to find the answer.
 
1) First make three groups of nine coins. balace two of them.
2) Again make three groups of three.Balance two of them.
3) Now there only three coins left to check out and that's easy. :biggrin:
 

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