Question 204427
a couple of important thoughts ...
___ you don't shake hands with yourself
___ Bill shaking hands with Sue is the same as Sue shaking hands with Bill


so, N people shake hands with N-1 people ___ and half of the handshakes are duplicates


28 = N(N-1) / 2 ___ 56 = N(N-1) ___ 8 * 7 = N(N-1) ___ 8 = N




this can also be evaluated by using nC2 and solving for n