The present ages of A and B are 42 and 36 years, respectively. After K years,…
2025
The present ages of A and B are 42 and 36 years, respectively. After K years, the ratio of ages of B to A will be 15:17. What is value of K?
- A.
7
- B.
8
- C.
9
- D.
10
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Correct answer: C
Let future ages after K years be: A → 42+K, B → 36+K.
Given (B : A) = 15 : 17 ⇒ (36+K)/(42+K) = 15/17.
Cross-multiply: 17(36+K) = 15(42+K).
612 + 17K = 630 + 15K.
17K − 15K = 630 − 612 = 18.
2K = 18 ⇒ K = 9.