Question

find n , 3. nP4=5. n-1P4​

Answer 1

Answer:

Given, 3 × P(n, 4) = 5 × P(n, 5)

∴ 3 × \dfrac{(n)!}{(n - 4)!} = 5 × [tex]\dfrac{(n)!}{(n - 5)!} < /p > < p > ⇒ 3 × [tex]\frac{n}{(n - 4)}

(n−4)!

(n)!

=5×[tex]

(n−5)!

(n)!

</p><p>⇒ 3×[tex]

(n−4)

n

= 5

⇒ 3n = 5n - 20

⇒ 2n = 20

⇒ n = 10

∴ n = 10