Difficulty: Medium
Correct Answer: 54 years
Explanation:
Introduction / Context:
Parent–child age problems often give a present-time multiple and a future-time ratio. Setting the parent as a multiple of the child’s present age, then applying the future ratio, yields a single unknown variable to solve.
Given Data / Assumptions:
Concept / Approach:
Cross-multiply to obtain a linear equation in s; compute s and then Sanyal’s age 3s.
Step-by-Step Solution:
Verification / Alternative check:
Six years later: father 60, son 24 ⇒ 60 : 24 = 5 : 2 ✓.
Why Other Options Are Wrong:
48/50/60/45 do not respect both the present multiple and the 5:2 future ratio when paired with a consistent son’s age.
Common Pitfalls:
Forgetting to add 6 to both ages; setting father = 3(s + 6) instead of 3s + 6 (the multiple applies to present ages only).
Final Answer:
54 years
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