Question

If npr =1320 and ncr =220 find the values of n and r

Answer 1

npr=n!/(n-r)! ncr=n!/(n-r)!r!
n!=1320(n-r)! n!=220(n-r)!r!
1320(n-r)!=220(n-r)!r!
1320=220r!
r!=6
r=3