Question down there to long for up here?

Question

A club of 10 students will form a Subcommittee consisting of three students. How many different such Subcomitee's can be formed?

Answer 1

Combinations of 10 over 3, that is

10! / 3! (10-3)! = 120

n ! is factorial of n = n x(n-1)x (n-2)x...x 1

Answer 2

the answer can be found by combinations.

ncr = n!/(r!(n-r)!)

10c3=10!/(3!(10-3)!)
10*9*8*7*6*5*4*3*2*1/(3*2*1(7*6*5*4*3*2*1))

=120

therefore 120 different subcommittees can be formed

Answer 3

10C3 = 10! / (7! * 3!) = 120