Question

Evaluate 9 P 4.

15,120
36
3,024
504

Evaluate 6 C 2.

30
720
120
15

Answer 1

formula for permutation is \[\huge\rm n P_r = \frac{ n! }{ (n-r)! }\]
n = 9
r =4
and for combination \[\huge\rm nC_r = \frac{ n! }{ r!(n-r)! }\]