The Professor
by Philip Newman
Submitted by Patient0:
A Professor and his wife decided to have a dinner party. They invited four other couples. During the evening, various guests and hosts greeted some of the others with handshakes. At the end of the evening, the Professor asked each other person at the party how many different people's hands he/she had shaken; he got nine different answers. Assuming that no two people in the same couple shook hands, and no two people shook hands more than once, how many handshakes did the Professor's wife receive?