Five mathematicians enter a room for a conference. If every person shakes hands with every other person in the room exactly once, how many handshakes occur in total?
10
The total number of handshakes among n people is n(n - 1) / 2. For 5 people, (5 × 4) / 2 = 10 handshakes.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Easy. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
More math riddles
I have two sisters. Each of my sisters has two brothers. How many children are in total in our family?
If five cats can catch five mice in five minutes, how many minutes will it take one cat to catch one mouse?
A lily pad doubles in size every single day. If it completely covers a pond in 30 days, on which day was the pond exactly half covered?
15 snowmen are shared equally among 3 friends. How many snowmen does each friend get?
If you multiply my age by itself, subtract 40, and then divide by 4, the result is exactly 9. How old am I?
Omar counts clovers in a pattern: 3, 5, 7, 9. How many clovers come next?