Question
Question: If <sup>n</sup>C<sub>4</sub> = 210, then <sup>12</sup>C<sub>n</sub>....
If nC4 = 210, then 12Cn.
A
33
B
22
C
11
D
66
Answer
66
Explanation
Solution
24n(n−1)(n−2)(n−3)=210.
n(n - 1) (n - 2) (n - 3) = 210 x 24 = 7 x 3 x 5 x 2 x 4 x 3 x 2
= 7 x 8 x 9 x 10.
n = 10.
12Cn = 12C10 = 12C2 = 212x11 = 66.