9514 1404 393
Answer:
17
Step-by-step explanation:
The number of handshakes among n people is n(n -1)/2. Then ...
n(n -1)/2 = 136
n(n -1) = 272 = 17×16*
n = 17
There were 17 people at the party.
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* This factoring can be facilitated by recognition that √272 ≈ 16.5, the number midway between the consecutive factors.
