Question

At a gathering of 10 people, each person must shake each other person's hand once. How many handshakes must there be?

Answer 1

Well how many people involve an handshake?

Answer 2

Two.

Answer 3

Exactly.

Answer 4

Is order important?

Answer 5

It is 10C2, but why isn't it 2^10?

Answer 6

Okay so you have the math right.

Answer 7

You assume that each people has a choice. The can shake hands or they can't shake hands.

Answer 8

They MUST shake hands. So you can't say 2^10 .

Answer 9

Thank you!

Answer 10

Welcome :) .