Delhi Police Constable Exam Model Paper 1

Let, the age of son be x and the age of mother be y
It is given that the son's present age is two-fifths of his mother's age.
$\mathit{x}=\frac{2}{5}\mathit{y}$ ----(i)
After 8 Years, the son will be one half of his mother's age
$\mathit{x}+8=\frac{1}{2}\left(\mathit{y}+8\right)$ ----(ii)
On solving eq (i) and eq(ii)
Hence, the age of the mother is 40 years now