Question

evaluate : n! / r! (n - r)! when n = 5 and r = 2 from permuatation and combination chapter​

Answer 1

$\frac{n!} {r! ( n - r )!}$

=>$\frac{5!}{2!(5 - 2 )!}$

=> $\frac{5!}{2 ( 3 )!}$

=> $\frac{5 ×4×3!}{2 ×3!}$

=> 5×2

=> 10

$\sf{\huge{Answer \:= \:10}}$