Question

Five years ago the sum of ages of the father and the son was $40$ years. At present, the ratio of their ages is $4:1$. The present age of father is:

• A. $30$ years
• B. $40$ years
• C. $45$ years
• D. $42$ years

Answer 1

The correct option is B $40$ years

Given, the ratio of present ages of father and son is $4:1$.

Let present ages be $4x$ and $x$, respectively.

$5$ years ago, age of the father was $4x-5$ years and age of the son was $x-2$ years, respectively

According to the question,

$4x-5+x-5=40$

$\Rightarrow 5x-10=40$

$\Rightarrow 5x=50$

$\Rightarrow x=10$

Present age of father $=4\times 10=40$ years