Question

Can someone please help Thank you

Answer 1

Formulas to solve given problems:
nPr = n! / (n-r)!
nCr = n! / ((n-r)! r!)

12P3 = P(12,3) = 12! / (12-3)! = 12! /9! =12*11*10 = 1320
10C7 = C(12,7) = 10!/((10-7)!7!) = 10!/(3!7!) = 10*9*8 / (1*2*3) = 120