Five couples were at a party. If each person shook hands exactly once with everyone else except his/her spouse, how many handshakes were exchanged? (Note: One obviously doesn't shake hands with oneself.)
Ten people at the party and each mus shake hands with eight other people BUT each hand shake involves two people
10 * 8 / 2 = 40 handshakes should cover it.
Thanks!
+82 
