Question

Find n, if ...
(01) 18 C ( n , 3 ) = 5 C ( n , 5 )
using permutations and combinations .
Need a full detailed answer .​

Answer 1

Answer:

given 18c(n,3) = 5 c(n,5)

Step-by-step explanation:

18×n(n_1)(n_3)/3×2 = 5 n( n_1)(n_2)(n_3)(n_4)/5×4×3×2

3 =(n_3)(n_4)/24

(n_3)(n_4) =72

n^2_7n+12 = 72

n^2_7n_60 = 0

n^2_12n+5n_60 =0

n(n_12)+5(n_12) = 0

(n+5)(n_12) = 0

n+5 = 0 n_12 = 0

n = _5 n = 12