Eighteen $years$ ago,a father was three times as old as his son. Now the father is only twice as old as his son. Then the sum of the present ages of the son and the father is

The age of the father is $30 \text{ years}$ more than the son's age. Ten $\text{years}$ hence,the father's age will become three times the son's age at that time. What is the son's present age in $\text{years}$?

The ratio of the present ages of Swati and Trupti is $4:5.$ $6 \text{ years}$ hence the ratio of their ages will be $6:7.$ What is the difference between their ages? (in $\text{years}$)

The average age of women and child workers in a factory was $15 \text{ years}$. The average age of all the $16$ children was $8 \text{ years}$ and the average age of women workers was $22 \text{ years}$. If $10$ women workers were married,then the number of unmarried women workers is:

$A$ man is $24$ years older than his son. In $2$ years,his age will be twice the age of his son. The present age of the son is (in years):

Present ages of $X$ and $Y$ are in the ratio $5:6$. Seven years hence the ratio will become $6:7$. What is the present age of $X$ in years?