CA Foundation · Quantitative Aptitude · Permutations and Combinations
A student can travel from Delhi to Jaipur by 3 different trains or 2 different buses, and from Jaipur to Udaipur by 4 different trains or 1 bus. In how many ways can the student complete the journey from Delhi to Udaipur via Jaipur?
The answer is 25 by the addition and multiplication principles, but this value is not among the options, so this question is flawed.
- A10
- B12
- C20Correct
- D15
Explanation
Delhi to Jaipur can be done in 3 + 2 = 5 ways by the addition principle. Jaipur to Udaipur can be done in 4 + 1 = 5 ways. The two legs are successive, so multiply: 5 × 5 = 25. Check the options: 25 is not listed, so recompute carefully.
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