Difference between revisions of "Nine weights"

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(Created page with 'A classic logic puzzle. ==Puzzle== On the table sit nine identical looking nuggets of gold. However, you know that one of the nine is a clever forgery. The only difference be…')
 
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[[Category: Logic]]
 
[[Category: Logic]]
 
[[Category: Pigeonhole principle]]
 
[[Category: Pigeonhole principle]]
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==See also==
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[[Twelve weights]] - you can use the scale three times to find a weight that is either lighter or heavier.  Quite a challenge.
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[[Six weights]] - you can use the scale twice to locate the heavy weight in each of three colors.

Revision as of 08:10, 5 April 2010

A classic logic puzzle.

Puzzle

On the table sit nine identical looking nuggets of gold. However, you know that one of the nine is a clever forgery. The only difference between the fake and the real nuggets is in weight: the fake gold weighs slightly less than the true gold. Unfortunately, this weight difference is not great enough to be noticed in human hands. Fortunately, you have a standard balance scale. Unfortunately, you may only use the balance scale twice. Fortunately, there is a way to find the fake gold even with these restrictions. How?

See also

Twelve weights - you can use the scale three times to find a weight that is either lighter or heavier. Quite a challenge.

Six weights - you can use the scale twice to locate the heavy weight in each of three colors.