In a room of 30 people, everyone shakes hands with everyone else exactly once. How many total handshakes occur?
435
Calculated using the combination formula n(n-1)/2, where n is 30. (30 × 29) / 2 = 870 / 2 = 435.
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: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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