Answer
$336$
Work Step by Step
RECALL:
$P(n, r) = \dfrac{n!}{(n-r)!}$
Use the formula above to obtain:
$P(8, 3) = \dfrac{8!}{(8-3)!}
\\P(8, 3) = \dfrac{8!}{5!}
\\P(8, 3) = \dfrac{8(7)(6)(5!)}{5!}$
Cancel the common factor $5!$ to obtain:
$P(8, 3) = 8(7)(6)
\\P(8, 3) = 336$