# I hav 9 gold coins that r identical exept for 1(counterfeit), how do I find it w 2 tries on a balanc scale?

I have 9 gold coins that are identical in appearance. However, one is counterfeit and weighs slightly less. Using a balance scale, how can I find the counterfeit coin in just two weighings?

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1. Divide the nine coins into three groups of three.

2. Put one group on one side of the scale, and a second group on the other side (the third side is left on the table). If the scales are uneven, then the counterfeit coin is in the group that is higher. If the scales are even, then the counterfeit coin is in the group that is still on the table.

3. Discard all the coins in the other two groups.

4. From the group with the counterfeit coin in it, set one coin on one side of the balance, and a second coin on the other side. (The third coin stays on the table, but separate from the six coins you’ve already eliminated.) If the scales are uneven, then the counterfeit coin is on the higher side of the scale. If the scales are even, then the counterfeit coin is on the table.