Processing math: 61%
Home / Aptitude Tests / Further Mathematics / If \(^{3x}C_{2} = 15...
If 3xC2=15, find the value of x?...

If 3xC2=15, find the value of x?

A.

2

B.

4

C.

5

D.

6

Correct answer is A

3xC2=3x(3x1)(3x2)!(3x2)!2!=15

3x(3x1)=309x23x30=0

9x218x+15x30=9x(x2)+15(x2)=0

(9x+15)(x2)=0

x = 2.