Question

The age of Sunil and his father are in the ratio 3:7. Four years later the sum of their ages will be 78 years. Which of the following represents the age of either Sunil or his father?

• A. 18 years
• B. 42 years
• C. 21 years
• D. 49 years

Answer 1

Answer: (C), (D)

49 years

Let the age of Sunil be $3x$.
Then, the age of Sunil's father would be $7x$.

Four years later,
Sunil's age = $3x+4$ and
Sunil's father's age = $7x+4$.

Then, the sum of their ages four years later $=3x+4+7x+4=10x+8$.

Given that, $10x+8=78$.
$\Rightarrow 10x=70\Rightarrow x=7$

$\therefore$ Present age of Sunil = 3 × 7
= 21 years
Present age of Sunil's father = 7 × 7
= 49 years