Multiple choice

The sum of ages of a father and a son is 45 years. 5 years ago, the product of their ages was four times the father’s age at that time. What is father’s present age ?

  1. 35 years

  2. 36 years

  3. 39 years

  4. 38 years

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let father's present age = F, son's present age = S. F + S = 45. Five years ago: (F-5)(S-5) = 4(F-5). If F-5 ≠ 0, then S-5 = 4, so S = 9. Then F = 45 - 9 = 36. Verifying: Five years ago, father was 31, son was 4. Product = 31 × 4 = 124. 4 × father's age = 4 × 31 = 124. ✓ Therefore father is 36 years.

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