Smile Always =)

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WISH TWO;Dont need, want him give high marks can already T^T
WISH THREE;

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Sunday, February 21, 2010

Smile always | 7:57 AM

VERSION 1!

Smile always | 7:32 AM

Thursday, February 18, 2010

VERSION 2!!!

Weigh coins 1 2 3 on the left and 4 5 6 on the right. Leave 7 and 8 at one side first.
Since the counterfeit coin is lighter, the weighing scale on either side will go up.

If the one on the left goes up, either of coins 1 2 3 is the counterfeit coin.
weigh coin 1 on the left and coin 2 on the right.
If it balances, it means that coin 3 is the counterfeit coin.
If one of the side goes up, the one that goes up is the counterfeit coin.

If the weighing scale balance, it means that either of coin 7 or 8 is the counterfeit coin.
weigh coin 7 and 8 on each side, the one that goes up is the counterfeit coin.

Smile always | 8:48 PM

Task: There are 3 versions of the counterfeit coin problem, each with increasing degree if difficulty. You are to solve each problem using any heuristics. Most importantily, list the thinking skills you have used to solve the problems.

Version one:

OO OO OO OO

You are given 8 coins. Of the 8 coins, one of them is a counterfeit coin which is lighter than the other coins. You are provided with a balance weighing scale. Using the balance weighing scale at most twice, explain the steps which you would take to identify the counterfeit coin.

Version 2:

OOO OOO OOO

Now, you are given 9 coins and 1 of them is a counterfeit coin. The counterfeit coin is heavier than the good coins. Explain how you would find the counterfeit coin using the balance weighing scale in only 2 weighings.

Version 3:

OOO OOO OOO OOO

Now, you are given 12 coins and 1 of them is a counterfeit coin. The counterfeit coin may be heavier or lighter than the good coin. Explain how you would find the counterfeit coin using the balance weighing scale in only 4 weighings.

Smile always | 8:00 PM