Suppose you have a balance scale with the fish on the left pan and an unknown weight on the right pan. You don't know the weight of the object on the right pan but it balances with the fish on the left.

Take the fish off the pan, cut it in half, put half of the fish on the table and the other half on the left pan. Add a 5 pound weight to the left pan. Again the scale balances. How much does the half fish on the table weigh?

Penny