Past double condition with a future age given: Hema will be 40 years old 10 years from now. Ten years ago, Hema was twice as old as Geetha. How old is Geetha today?
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A25 years
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B20 years
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C15 years
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D35 years
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E30 years
Answer
Correct Answer: 20 years
Explanation
Introduction / Context:We combine a known future age for Hema with a past-time multiplicative relation involving Geetha. First find Hema’s present age, then move 10 years back to apply the “twice” condition and step forward to the present for Geetha.
Given Data / Assumptions:
- Hema in 10 years = 40 ⇒ Hema now = 30.
- Ten years ago: Hema = 2 × Geetha.
Concept / Approach:Ten years ago, Hema was 20 (since 30 − 10). If that was twice Geetha's age then, Geetha was 10 at that time. Therefore, now Geetha is 20.
Step-by-Step Solution:1) Hema now = 40 − 10 = 30.2) Ten years ago Hema = 20.3) 20 = 2 × (Geetha then) ⇒ Geetha then = 10.4) Geetha now = 10 + 10 = 20.
Verification / Alternative check:Check the future statement: Hema in 10 years = 40 (true). Past statement: 20 and 10 satisfy the 2× relation (true).
Why Other Options Are Wrong:
- 25/15/35/30 do not satisfy both the past multiple and the future age constraint together.
Common Pitfalls:Confusing “10 years hence” with “10 years ago” or failing to compute Hema’s present age correctly before applying the past condition.
Final Answer:20 years