There are persons at a party, and if each two of them shake hands with each other, how many handshakes happen at the party?
A number of handshakes happen at the party.
The combination is the number of ways of selecting objects such that the order of selection is not to be counted.
Combination Formula:
The total number of handshakes is the same as the number of ways of selecting persons among persons i.e.,
Hence, handshakes happen at the party.