Question

At the end of a business conference, ten people present shake hands with each other once. How many handshakes will be there all together?

• A. $20$
• B. $45$
• C. $55$
• D. $90$

Answer 1

The correct option is B $45$

First one man will shake hands with 9 people, then other will shake with 8 people, and so on.
Thus, total handshakes are = $9+8++6+5+4+3+2+1=45$