February 2nd, 2006


another logic puzzle

This came up today. I'm not 100% sure the answer I have in mind is unique, but I think it is.

You and your spouse invite 4 other couples over for a dinner party. During the course of the party, many people shake hands with other people, except that no one shakes hands with their partner or themselves. At the end of the party, you realize that each of the other 9 people (that is, everyone but you) shook a different number of hands from each other. How many different hands did you shake?

Again, the answer doesn't involve tricks, like some people shaking with both their left and right hands or shaking the hand of someone not at the party. All comments screened for now, like before. Questions and bad guesses will be unscreened sooner; good guesses and right answers will be unscreened later. No googling allowed! Comments now contain spoilers.