Difficulty: Easy
Correct Answer: 3 years
Explanation:
Introduction / Context:Here a fractional multiplier ties present age to a past age (at marriage), followed by a simple fraction for the child's age.
Given Data / Assumptions:
Concept / Approach:Equate the two expressions for present age to find x, then compute present age and take one-tenth for the son.
Step-by-Step Solution:
1) x + 6 = (5/4) * x. 2) Multiply both sides by 4: 4x + 24 = 5x → x = 24. 3) Present age = x + 6 = 30. 4) Son's age = (1/10) * 30 = 3 years.Verification / Alternative check:Check multiplier: (5/4) * 24 = 30, matching the present age used to compute the son's age.
Why Other Options Are Wrong:They correspond to incorrect algebra (e.g., treating 1.25x as x + 1.25).
Common Pitfalls:Forgetting that “married 6 years ago” means present age exceeds marriage age by exactly 6 years, not 6%.
Final Answer:3 years
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