A colleague of mine asks this question during job interviews: Say I'm making pancakes. The first one is burned on both sides. The second one is better-only one side burned. The third one is okay on both sides. I choose a pancake at random and observe that one side is not burned. What are the chances the other side isn't burned, either?— Danny Wnek, New York City
The chances are two out of three. The pancake you chose was one of these two: the okay/burned one or the okay/okay one.
Given this choice, you could be looking at any of three "okay" sides. Of those three sides, two of them are okay on the other side, too.
I'll bet those applicants are relieved when that interview is over!