The sum of the present ages of a father and his son is 78 years. After five years, the ratio of their ages becomes 7 : 4. What is the present age (in years) of the father?
Answer & explanation
Correct answer: option 2
The ratio of ages of a father and son five years ahead is 7 : 4
To calculate their present ages, we subtract 5 from each
Father's present age = (7r - 5) years
Son's present ages = (4r - 5) years
Given, Sum of present ages = 78 years
⇒ (7r - 5) + (4r - 5) = 78
⇒ 11r - 10 = 78
⇒ 11r = 88 or r = 8
Present ages of father = 7x8 - 5 = 51 years