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?

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