SOLUTION: There are 12 people in a room. Each person will shake hands with everyone else in the room just once. How many total handshakes will there be? Thanks in advance for the help!

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Question 324197: There are 12 people in a room. Each person will shake hands with everyone else in the room just once. How many total handshakes will there be?
Thanks in advance for the help!

Answer by galactus(183) About Me  (Show Source):
You can put this solution on YOUR website!
For the first person, there will be 11 handshakes.
For the second person, there will be 10 handshakes because that person has
shaken the hand of the first person.
So for the third there will be 9 handshakes and so on and so on.
So there will be 11+10+9+8+7+6+5+4+3+2+1 handshakes.
This is equal to (12*11)/2= 66
If there are n people in the room, then there are n(n-1)/2 handshakes.