+130516 The first person shakes 5 other hands........the second person shakes 4 other hands (he has already shaken the first person's hand)......the third person shakes three other hands (since he has already shaken the hand of the first two), etc.
So we just have the sum of the first five numbers = 5 * 6 / 2 = 15 handshakes
+130516 The first person shakes 5 other hands........the second person shakes 4 other hands (he has already shaken the first person's hand)......the third person shakes three other hands (since he has already shaken the hand of the first two), etc.
So we just have the sum of the first five numbers = 5 * 6 / 2 = 15 handshakes
