Multiple choice general knowledge math & puzzles

At a party, everyone shook hands with everybody else. There were 66 handshakes. How many people were at the party?

  1. 10

  2. 11

  3. 12

  4. 15
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The number of handshakes in a group of n people is given by the combination formula n times (n - 1) divided by 2. Setting this equal to 66 gives n times (n - 1) equal to 132. Solving this quadratic equation yields 12 people.

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