Given:
Number of people in the conference = 10
Each person shakes hands with others.
Concept used:
When n people shake hands with each other, the total number of handshakes =nC2
Calculation:
Total number of handshakes =10C2= (10× 9)/2 = 45 handshakes.
When 10 people are shaking hands, each one will shake hands with 9 others.
Then the total number of handshakes = 10× 9 = 90
(Remember that, when A shakes hands with B, B is also shaking hands with A. That means, we are counting one handshake twice, one from A's side and the other from B's side)
The total number of handshakes in actual = 90/2 = 45 handshakes.
∴ The total number of handshakes is 45.