Everyone shakes hands with everyone else in a room. Total number of handshakes is 78. Number of persons=?	Choose the correct answer
A) 13
B) 12
C) 11
D) 15
E) 16
In a room of n people, the number of possible handshakes is C(n,2) or n(n-1)/2   So n(n-1)/2 = 78 OR n(n-1)=156 OR n=13   13nswer is (13)
<result>A</result>
Everyone shakes hands with everyone else in a room. Total number of handshakes is 78. Number of persons=?