Difficulty: Easy
Correct Answer: 60 years, 32 years
Explanation:
Introduction / Context:
Age-ratio problems often require setting up variables from the initial ratio and then applying a time shift to match a future ratio. Solving the resulting equation yields the scale factor and thus the present ages.
Given Data / Assumptions:
Concept / Approach:
Cross-multiply the future ratio to solve for x. Then compute actual ages by multiplying the ratio terms by x.
Step-by-Step Solution:
3(15x + 10) = 5(8x + 10)45x + 30 = 40x + 50 → 5x = 20 → x = 4Ages now: 15x = 60 years; 8x = 32 years
Verification / Alternative check:
After 10 years: 70 and 42, ratio 70:42 = 5:3, so the condition holds.
Why Other Options Are Wrong:
Reversed orders or unreduced ratios do not satisfy the future ratio condition when checked.
Common Pitfalls:
Forgetting to add 10 to both ages or cross-multiplying incorrectly in the ratio equation.
Final Answer:
60 years, 32 years
Discussion & Comments