Ages (marriage reference and fractional multiple): Radha married 6 years ago. Today her age is 1.25 times her age at marriage. Her son's age is one-tenth of her present age. Find the son's age.

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:

• Let marriage age be x years.
• Present age = 1.25 * x = (5/4) * x.
• Also, present age = x + 6 (since marriage was 6 years ago).
• Son's age = (1/10) * present age.

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:

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