SOLUTION: There were 12 friends each greeted each other by shaking hands.How many hand shakes took place

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Question 1045032: There were 12 friends each greeted each other by shaking hands.How many hand shakes took place
Found 2 solutions by KMST, ikleyn:
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Each friend shook 11 hands, so they would report 11%2A12 shakings,
but since each shake was reported twice,
there were 11%2A2%2F2=11%2A6=66 shakes.

Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
.
%2811%2A12%29%2F2 = 66 shakes.