Everyone shakes hands with everyone else in a room. Total number of handshakes is 66. Number of persons=?
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 = 66 OR n(n-1)=132 OR n=12Answer is (b)
1) Algebra-101 2) Sequences 3) Set combinatorics 4) 3-D geometry
My GMAT story
GMAT Club Premium Membership - big benefits and savings