Question

Tentukan nilai n, jika = (nK2×5K2 )/nK4

Terima kasih..... :)

Answer 1

N K2 = n ! / (n-2)! . 2! = n(n-1)/ 2
5K2 = 5 !/ (5-2)! .2! = 5!/ (3!.2! ) = 10
nK4 = n! / (n-4)! . 4! = n(n-1)(n-2)(n-3) /(24)
.
(nK2. 5K2) / (nK4) =
= n(n-1)/2 . (10) / ( n(n-1)(n-2)(n-3) /(24)
=  5 (24)/ (n-2)(n-3)
 = 120/ (n^2-5n+6)