Question

Seven people come to a party and shake hands with each other. If each person shakes the hand of every other person, how many handshakes occur?

There will be 49 handshakes.

Answer 1

49 handshakes

Explanation:

By the Fundamental Counting Principle, if there are 7 ways to shake hands with each other and 7 ways to shake hands with every other person, then there are 7*7=49 ways to do both things, therefore 49 handshakes occur.

Answer 2

21.

Explanation:

I think its the number of combination of 2 form 7.

That is (7*6)/(2*1)

= 21.