There are 8 balls. 7 of them weigh the same. 1 of them has a different weight, (you don't know if it's heavier or lighter). How do you find the odd ball with 2 weighs? You have nine balls of the same size. Eight of them weigh the same, and one of them weighs slightly more or less. How can you find the ball that is different by using a balance and only three weightings?