The age of a father is three times that of his son. After $5$ years,double the father's age will be five times the son's age. The present age of the father and son (in $years$) is:

The ratio of the present ages of two brothers is $1:2$ and $5 \text{ years}$ back,the ratio was $1:3$. What will be the ratio of their ages after $5 \text{ years}$?

After replacing an old member by a new member,it was found that the average age of five members of a club is the same as it was $3$ years ago. The difference between the ages of the replaced and the new member is (in years):

The present age of Romila is $\frac{1}{4}$ that of her father. After $6\, \text{years}$, her father's age will be twice the age of Kapil. If Kapil celebrated his fifth birthday $8\, \text{years}$ ago, what is Romila's present age? (in $\text{years}$)

Six years ago,the ratio of the ages of Kunal and Sagar was $6:5$. Four years hence,the ratio of their ages will be $11:10$. What is Sagar's age at present? (in years)

Eighteen $years$ ago,the ratio of $A$'s age to $B$'s age was $8: 13$. Their present ages are in the ratio $5: 7$. What is the present age of $A$ (in $years$)?