- A11
- B33
- C66
- D12
Step-by-Step Solution
A handshake is a selection of 2 people from , so C,2) = 66, i.e. and . Since .
Answer: D) 12
At a meeting every person shook hands exactly once with every other person present, and 66 handshakes took place in all. Using combinations, find how many people attended the meeting.
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