Father–Son — “A father says: ‘I was three times your present age when you were born.’ The father is now 48. How old was the boy 4 years ago?”

Introduction / Context:
The sentence compares the father’s age at the son’s birth (a past time) with the son’s present age. Translate it carefully into a linear equation, then answer the question about the boy 4 years ago.

Given Data / Assumptions:

• Father’s present age = 48.
• Let son’s present age = x.
• At son’s birth (x years ago), father’s age = 48 − x.
• Statement: 48 − x = 3x.

Concept / Approach:
Age differences are constant, but here we directly set father’s past age equal to a multiple of the son’s present age. Solve for x and then subtract 4 for “4 years ago.”

Step-by-Step Solution:

Verification / Alternative check:
At birth: father 48 − 12 = 36, which is indeed 3 × 12 (the son’s current age). Consistent.

Why Other Options Are Wrong:
10/12/16/24 do not represent “boy’s present age 12, four years earlier” which must be 8.

Common Pitfalls:
Setting 48 = 3x (missing the “at birth” shift), or subtracting 4 from father’s age rather than the boy’s age.

Final Answer:
8 years