Madhya Pradesh Police Exam Model Paper 8

Given:
Ratio of ages of father and son, 7 years ago = 4 : 1
Ratio of ages of father and son, 7 years hence = 2 : 1
Calculation:
Let the age of father and son 7 years ago be 4x and x respectively
Age of father 7 years hence $=4\mathit{x}+7+7$
$\Rightarrow 4\mathit{x}+14$
Age of son 7 years hence $=\mathit{x}+7+7$
$\Rightarrow \mathit{x}+14$
Now, according to question,
$\left(4\mathit{x}+14\right)/\left(\mathit{x}+14\right)=2/1$
$\Rightarrow 4\mathit{x}+14=2\mathit{x}+28$
$\Rightarrow 2\mathit{x}=14$
$\Rightarrow \mathit{x}=7$
Present age of father $=4\mathit{x}+7$
$\Rightarrow 4\times 7+7$ years
⇒ 35 years
Age of son $=\mathit{x}+7$
$\Rightarrow 7+7$ years
⇒ 14 years
Required ratio = 35 years : 14 years
$\Rightarrow 5:2$
∴ The ratio of their present ages is 5 : 2