Question

Thirteen guests have participated in a dinner. The number of handshakes that happened in the dinner is:

Options

• 715

• 78

• 286

• 13

Answer 1

78

Explanation:

To handshakes, we need two guests.

Number of selecting 2 guests from 13 is 13C₂ = `(13 xx 12)/(2 xx 1)` = 78