Answer:
n = 10
Step-by-step explanation:
n! / 6!(n - 6)! = n! / 4!(n - 4)!
6!(n - 6)! = 4!(n - 4)!
6!(n - 6)! / 4!(n - 4)! = 1
6*5(n - 6)! / (n - 4)! = 1
30(n - 6)! = (n - 4)!
(10-6)! = 4 * 3 * 2 * 1 and
(10 -4)! = 6*5*4*3*2*1
Dividing (10-4)! / (10-6)! = 30
so n = 10.
