Multiple choice general knowledge

Every person in a room shook hans with every OTHER person in the room. Totally there were 66 hand shakes .Find the total persons in the room

  1. 6

  2. 12

  3. 36

  4. 21

  5. 11

  6. 10
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For n persons each shaking hands with every other person, total handshakes = n(n-1)/2. If handshakes = 66, then n(n-1) = 132, giving n = 12. Check: 12 × 11/2 = 66.

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