$10$ years ago,Mohan was thrice as old as Ram was,but $10$ years hence,he will be only twice as old as Ram. Find Mohan's present age (in years).

The age of a father is twice that of his elder son. Ten years hence,the age of the father will be $3$ times that of the younger son. If the difference of ages of two sons is $15 \text{ years}$,the age of the father is (in $\text{years}$)

$7$ years ago,the ages (in years) of $A$ and $B$ were in the ratio $4:5$; and $7$ years hence they will be in the ratio $5:6$. The present age of $B$ is (in years):

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:

$15$ years hence,Rohit will be just four times as old as he was $15$ years ago. How old is Rohit at present?

$A$ father is now $3$ times as old as his son. $5$ years back,he was $4$ times as old as his son. The age of the son is: