1. ## urgent

n people shake hands at the start of the meeting . If there are 36 handshakes in all , find the value of n .

2. ${n \choose 2} = 36 \mbox{ then }n=?$

3. n
C = n(n-1) =36
2 1*2

Combinations ( ways to choose two from n people )
solve quadratic equation and ignore negative solution