A persons present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present?
32 years
36 years
40 years
48 years
Explanation:
Let the mothers present age be $ x $ years.
| Then, the persons present age =$ \left(\dfrac{2}{5} x\right) $years. |
| $\therefore \left(\dfrac{2}{5} x + 8\right) $=$ \dfrac{1}{2}\left(x + 8\right)$ |
$\Rightarrow$ 2$\left(2x + 40\right)$ = 5$\left(x+ 8\right)$
$\Rightarrow x $ = 40.