Q. If $\frac{1}{^{5} C _{r}} + \frac{1}{^{6} C _{r}} = \frac{1}{^{4} C _{r}}$ , then the value of $r$ equals to

2443 225 WBJEEWBJEE 2016Permutations and Combinations Report Error

A

$4$

B

$2$

C

$5$

D

$3$

Solution:

Correct answer is (b) $2$