A test consists of 12 questions out of which candidates are to answer 10. If the first 6 are compulsory, in how many ways can each candidate select her questions?
-
A.
40 -
B.
25 -
C.
15 -
D.
10
Correct Answer: Option C
Explanation
The first 6 questions can only be selected in 1 way.
The remaining 4 questions can be selected in (^{6}C_{4}) ways.
= (frac{6!}{(6 – 4)! 4!} = 15)