sentence1: There are 8 balls . 7 of them weigh the same . 1 of them has a different weight , -LRB- you do n't know if it 's heavier or lighter -RRB- . How do you find the odd ball with 2 weighs ?
sentence2: 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 ?