The present age of a father is twice the present age of his son. Five years ago, the father was three times as old as his son. What is the present age of the son?
- 5 years
- 8 years
- 10 years
- 15 years
Show answer and solution
Correct answer: C. 10 years
Let the son's present age be x years.
Then the father's present age is 2x years.
Five years ago, son was (x − 5) and father was (2x − 5).
**The condition gives:** 2x − 5 = 3(x − 5) = 3x − 15. Solving: 2x − 3x = −15 + 5
so −x = −10 and x = 10. The son is 10 years old now (and father is 20).
**Verify:** five years ago son was 5, father was 15 = 3 × 5. ✓