Ages (nested family offsets): Your age is 10 years less than half your mother's age. Your mother is 5 years younger than your father, who is 45. Find your present age.
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A20 years
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B15 years
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C10 years
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D5 years
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E12 years
Answer
Correct Answer: 10 years
Explanation
Introduction / Context:Composing two offsets (mother relative to father, you relative to mother) gives a simple linear chain. Work from the known father's age downward to obtain the required value cleanly.
Given Data / Assumptions:Father = 45 ⇒ Mother = 45 − 5 = 40 ⇒ You = (1/2)*40 − 10.
Concept / Approach:Substitute step by step; avoid doing everything at once to reduce mistakes in multi-clause statements.
Step-by-Step Solution:
Mother = 40. Your age = 20 − 10 = 10 years.Verification / Alternative check:Half of mother's age is 20; you are 10 less than that, hence 10 (✓).
Why Other Options Are Wrong:They result from halving the wrong person's age or subtracting 10 in the wrong place.
Common Pitfalls:Confusing “5 years younger than” with “5 times younger,” or halving after subtracting 10.
Final Answer:10 years