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Heavy Weight
after Martin Gardner

There is a set of nine identical weights and simple scales (without any measures) - just as shown on the left. It is known that one weight is a little bit heavier than the eight others.

Using only the scales can you identify the heavier weight in two weighings only?

To solve this puzzle you may use the interactive version of it presented here. Simply put the weights on the scale pans and follow the instructions which will appear in the top right corner.

To move a weight on the scales first highlight it with clicking and then click the respective spot on either of the two pans. To remove a weight from the scales highlight it and then click the respective spot outside the scales.

To make the numbers of the weights appear (just as help in solving) click the Labels button. To make them disappear click the button again.

Note. The heavier weight is generated randomly each time you start to solve the puzzle from the beginning.

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