7 years ago, a father was three times his son’s age. If the son is 21 now, how old is the father now?

Question: 7 years ago, a father was three times his son’s age. If the son is 21 now, how old is the father now?

1. 50 years
2. 48 years
3. 49 years
4. 51 years

Correct Answer: C — 49 years

Explanation: Father’s past age = 3 × son’s past age; add elapsed years for present age.
Father now = 3(21 − 7) + 7 = 49 years.