If n P r = 720 and n C r = 120 then find the value of r.

Question

Philoid · Accepted Answer

Given: ⁿP_r = 720 & ⁿC_r = 120 Need to find: Value of r We know that, ⁿP_r = r! X ⁿC_r Putting the values, ⇒ 720 = r! X 120 ⇒ r! = 6 = 3! ⇒ r = 3.