Difficulty: Easy
Correct Answer: 36 years
Explanation:
Introduction / Context:Present and future multiplicative relations give two equations. Solving yields present ages directly.
Given Data / Assumptions:
Concept / Approach:Substitute the present relation into the future condition and solve for R, then compute S.
Step-by-Step Solution:
3R + 12 = 2(R + 12)3R + 12 = 2R + 24 ⇒ R = 12Therefore S = 3 × 12 = 36Verification / Alternative check:
In 12 years: S = 48, R = 24 ⇒ 48 = 2×24 ✓Why Other Options Are Wrong:
Common Pitfalls:Using S = 2R initially; forgetting that both grow by the same amount (12) in the future relation.
Final Answer:36 years
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