Question 129
In a group of 20 people, some people exchange handshakes.
a) We count how many handshakes each person has given and we add up all these numbers. Show that the result is even.
b) Is it possible that in a group of 99 people each person has given exactly 3 handshakes?
a) We count how many handshakes each person has given and we add up all these numbers. Show that the result is even.
b) Is it possible that in a group of 99 people each person has given exactly 3 handshakes?