Difficulty: Medium
Correct Answer: 35 years
Explanation:
Introduction / Context:We combine a difference-of-ages condition with a past multiple relation. Express both conditions as equations and solve for present ages.
Given Data / Assumptions:
Concept / Approach:Let present ages be M and D. Then M = D + 25, and M − 5 = 6(D − 5). Solve for D first, then compute M.
Step-by-Step Solution:
M = D + 25M − 5 = 6(D − 5)Substitute: (D + 25) − 5 = 6D − 30D + 20 = 6D − 30 ⇒ 50 = 5D ⇒ D = 10Therefore, M = 10 + 25 = 35Verification / Alternative check:
Five years ago: Mother 30, Daughter 5 ⇒ 30 = 6*5 ✓Why Other Options Are Wrong:
Common Pitfalls:Using M − D = 25 but forgetting to subtract 5 from both in the past relation; or replacing “six times” with “six more.”
Final Answer:35 years
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