A 10 person student council will be selected from 18 students at a school. How many poss are there for this council?

Answer 1

combinations of 18 taken 10 at a time
= 18!/[ 10!(18-10)!]

= 18*17*16*15*14*13*12*11/
(8*7*6*5*4*3*2)

= 17*16*15*14*13*12*11/(8*7*5*4*2)

= 17*15*14*13*12*11/(7*5*4)

= 17*3*2*13*3*11

= 43,758