You have 12 coins, six weigh 24 grams and six weigh 25 grams. You also have the broken scale from Five Weights and a Broken Scale.

Sort the 12 coins into the group of 24g coins and the group of 25g coins using that broken scale no more than 9 times.

(In reply to re: Solution, I think. by Federico Kereki)

The scale is broken. The 24g coin and the 25g coin will appear to be equal. It takes a difference greater than 1.5g to register inequality. You need at least two coins on both sides of the scale to discover a heavier weight. 

Solving this puzzle will take an exacting case-by-case approach id done manually, or a computer program might discover it.

 

Edited on October 20, 2007, 6:51 pm

Posted by Penny on 2005-06-28 14:13:53