Question

what is the awnser to david is the president of his student council when the leadership team met for the first time he asked each person to shake everyones hand if there were six people at his meeting,how many handshakes were made?

Answer 1

One way to solve this is to ask "How many ways can 2 people be chosen from 6 people?"

combinations = 6! / [2! * (6-2)!] = 6 * 5 * 4! / 2 * 4!

= 6 * 5 / 2 = 15 handshakes

Source: 1728.com/puzzle3 (see puzzle 55)