The present age of Salil's mother is three times Salil's present age. After 5 years, their ages will add up to
70 years. Find their present ages. [Page No. 21]

Let Salil's present age be $z$ years.

Then, mother's age = $3z$ years.

After 5 years,

Salil's present age = $(z + 5)$ years

Mother's age = $(3z + 5)$ years

According to Problem,

$$(z + 5) + (3z + 5) = 70$$

$$\Rightarrow 4z + 10 = 70$$

$$\Rightarrow 4z = 60$$

$$\Rightarrow z = 15$$

Hence, Salil's present age = 15 years;

Mother's present age = 3(15) = 45 years.