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