Larry was a manager working out of a freight office near Atlanta. Upset with early-morning misuse of his computer, Larry found solace in his favorite sport - golf - which is the subject of today's Brain Game. Enjoy:

Larry had 9 golf balls, one of which was a slightly lower weight than each of the others. He also had a small, old-fashioned, two-sided scale.

By using the scale only TWICE,
how could Larry determine
which golf ball was the odd one out?

Here is the SOLUTION.

THE SOLUTION:

Larry grouped the golf balls into three groups of three: A, B, and C.

For the first weighing, Larry put the A balls on one side of the scale, and the B balls on the other. From this point, there were three possibilities: (1) A was lighter, (2) B was lighter, or (3) the sides were the same weight.

1. If A was lighter, he knew the lighter ball was in group A, so he cleared the scale and - for his second weighing - placed one ball from group A on each side of the scale. If one side was lighter, that was the lighter ball. Otherwise, the third ball from group A was the lighter one.

2. If B was lighter, he knew the lighter ball was in group B, so he cleared the scale and - for his second weighing - placed one ball from group B on each side of the scale. If one side was lighter, that was the lighter ball. Otherwise, the third ball from group B was the lighter one.

3. If A and B were the same, then the lighter ball had to be in group C. Larry cleared the scale and - for his second weighing - placed one ball from group C on each side of the scale. If one side was lighter, that was the lighter ball. Otherwise, the third ball from group C was the lighter one.