There is a meeting organised every person shake hands with the other only onceif there are 60 shake handshow many persons are there in the meeting?

if there are 60 shakehands ,then der shoud be 12 person in the meeting .

( 12 * 11)/2 = 66 where (11 * 10)/2 =55...

Formula to derive: if there are 'n' persons ,

number of handshake= (n * (n-1)) / 2