Handshakes riddle
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In a get-together i counted the number of handshakes that were exchanged. There were 28 altogether.
Can you tell me how many how many guests were present ? 
Best answer
8
In a group of N people everyone shake hands with N-1 other persons.
When we multiply N with N-1 we are counting every handshake twice (A=>B is the same as B=>A)
So the number of handshakes is N(N-1)/2.
Fill in 8 and we get 8*7/2 = 28
When we multiply N with N-1 we are counting every handshake twice (A=>B is the same as B=>A)
So the number of handshakes is N(N-1)/2.
Fill in 8 and we get 8*7/2 = 28
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