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From: liul@il.us.swissbank.com (Lucas Liu)
Subject: re: need help
Message-ID: <1995Mar8.224801.23354@il.us.swissbank.com>
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Organization: Swiss Bank Corporation CM&T Division
Date: Wed, 8 Mar 1995 22:48:01 GMT
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I've actually seen this brain teaser before, but usually you are told  if  
the counterfit is heiver or leighter than the rest.  What you do is place  
5 on each pan, if they are balanced, then you know one of the two you did  
not weigh is the counterfeit, then weigh the two and if the counterfeit is  
the heavier, then you know that the heavier of the two is it.
If, when you weigh the two sets of 5, and they are not balanced, then take  
the heavier( if the counterfeit is heavier than the rest or lighter if the  
counterfeit is leighter).  Then from those five, place two in each pan, if  
they are balanced then it is the one you did not weigh, if they are not  
balanced, then again take the heavier(again if the fake is heavier, or  
lighter if the fake is lighter) set of two and weigh them, placing one in  
each pan and the heavier is the fake.  If the fake is lighter, then follow  
the above logic except replace the word heavier with lighter.
In any case, the solution can be found in min of 2 weighs and a max of 3  
weighs.
