Solution : 

Let us take the present age of mother and her daughter as 'x' and 'y'.

Given:

Mother's age is 5 times the age of her daughter's .

x = 5 y --------> 1 

After 5 years, mother's age is 3 times the age of her daughter's. 

(x + 5 ) = 3 ( y + 5 )

x + 5 = 3y + 15

Substituting equation 1 here we get

5y + 5 = 3y + 15

5y - 3y = 15 - 5

2y = 10

y = 10 /2

y = 5

Substituting the value of y in eqn 1 we get

x = 5 × 5

x = 25

So, the mother's age is 25 years 

The correct option is 3). 25 years