Tell whether each situation is a permutation or combination.
Nine people gather for a meeting. Each person shakes hands with every other person exactly once. How many handshakes will take place?
So since we are shaking hands in this question, right, it doesn't matter if a shakes bees hand or be shakes A's hand. That's the same hand shape. So this becomes a combination problem of having nine people, and we want to of them to shake hands. So this is nine times 8/2 times one, which is 72/2 for 36.