If 6Pr = 360 and If 6Cr = 15, find r ?

Answer: Option C

ⁿP_r = ⁿC_r × r!
⁶P_r = 15 × r!
360 = 15 × r!
r! = $$\frac{360}{15}$$ = 24
r! = 4 × 3 × 2 × 1
⇒ r! = 4!
Therefore, r = 4