Number of Handshakes at UN Meeting: 15

[rainbow1]

at a United Nations meeting, a group of 15 delegates meet to discuss an international peace treaty. If all of the delegates shake hands with one another, how many handshakes are exchanged?

 

[HOI]

That should be straight forward. In a group of n people each person shakes hands with the n-1 other people. That would be a total or n(n-1) except that each had shake involves two people. The total number of hand shakes is n(n-1)/2.