How many handshakes will happen if 100 people walk into a room and none of them have ever met before? Assume that everyone shakes hands with every other person exactly once.
+128474 Note that if we had 3 people, A, B , C.....the number of handshakes = 3
AB AC
BC
Note that if we only had 4 people, A,B, C, D.....the number of handshakes = 6
AB AC AD
BC BD
CD
This implies that for n peole, the number of handshakes is n ( n - 1) / 2
So....for 100 people we have
100 (100 - 1) / 2 =
50 * 99 =
4950 handshakes
