The ratio of two numbers a and b is 3:5. If 2 is added to both the numbers, the ratio becomes 2:3. Find b.
Correct answer: B. 10
- A. 15
- B. 10
- C. 8
- D. 5
Explanation
Let a = 3k and b = 5k. After adding 2 to each number, (3k + 2):(5k + 2) = 2:3, so 3(3k + 2) = 2(5k + 2), giving 9k + 6 = 10k + 4 and k = 2. Hence b = 5k = 10. The likely trap is option a, 15, which is the original ratio value if k is incorrectly taken as 3.
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