In a meeting room with 10 people, every person shakes hands with every other person exactly once. How many total handshakes occur?
45
The formula for combinations of pairs from n items is n × (n - 1) / 2. For 10 people, this is 10 × 9 / 2 = 45 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: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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