In a party there are 20 persons. If every person shook hand with every other person in the party exactly once, find the total number of handshakes exchanged in the party.

Thirty members attended a party. If each person shakes hands with every other person exactly once. Then find the number of handshakes made in the party.

In a party, there are 10 married couples. Each person shakes hands with every person other than her or his spouse. The total number of handshakes exchanged in that party is ___

In a party, every person shakes his hand with every other person only once. If total number of handshakes is 210, then find the number of persons.

Every two persons shakes hands with each other in a party and the total number of handis 66. The number of guests in the party is

Every two persons shakes hands with each other in a party and the total number of handis 66. The number of guests in the party is

Every person in a room , shake hands with every other person . The total number of handshakes it 45. The number of person in the room is .

In a conference of 8 persons, if each person shakes hand with the other one only, then the total number of shake hands shall be

There are n married couples at a party. Each person shakes hand with every person other than her or his spouse. Find the total m of hand shakes.

There are n married couples at a party. Each person shakes hand with every person other than her or his spouse. Find the total m of hand shakes.