The present age of father is twice that of the elder son. 10 years later the age of the father will be three times that of the younger son. If the difference of ages of the two sons is 15 years, the age of father is
- A. 50 years
- B. 100 years
- C. 70 years
- D. 60 years
Answer: A. 50 years
Explanation: Let father's age be F, elder son E, younger son Y. F = 2E, (F+10) = 3(Y+10), and E − Y = 15. Substituting E = F/2 and Y = F/2 − 15 gives F + 10 = 3(F/2 − 5) = 1.5F − 15 => 0.5F = 25 => F = 50 years.