Question

Tentukan nilai n jika nCn-2 = 190

Answer 1

N ! /(n-2)! 2!  = 190
n(n-1) / 2 = 190
n(n-1) = 380
n² - n - 380 = 0
(n -20)(n+19) = 0
n + 19=  0 atau n - 20 = 0
n = -19 atau n = 20
.
n = 20