At a conference, 10 members shook hands with each other before and after the meeting. How many hand shakes occurred before?

100

None of these

The formula to find the number of handshakes between n people is:

Handshakes = 𝑛(𝑛−1)/2

Here, n = 10

10 × 9/2 = 45

So, 45 handshakes occurred before the meeting.