CA Foundation · Quantitative Aptitude · Permutations and Combinations
A student must choose 2 optional subjects from 6 available subjects. In how many ways can the choice be made?
The choice can be made in 15 ways. Since the order of subjects does not matter, the number is 6C2, which equals 15. Using 6P2 gives 30, which counts each pair twice.
- A12
- B15Correct
- C30
- D36
Explanation
Order does not matter, so 6C2 = 6x5/2 = 15. The value 30 is 6P2, which wrongly counts order.
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