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 $years$)?

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 $5 \text{ years}$?

The ratio of the ages of Anubha and her mother is $1:2$. After $6$ years,the ratio of their ages will be $11:20$. What was the ratio of their ages $9$ years ago?

The average age of $30$ students of a class is $14$ years $4$ months. After the admission of $5$ new students,the average age becomes $13$ years $9$ months. The youngest of the five new students is $9$ years $11$ months old. What is the average age of the remaining $4$ new students?

$10$ 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 ages of $Ram$ and $Shyam$ differ by $16 \, \text{years}$. $6 \, \text{years}$ ago,$Shyam$'s age was thrice that of $Ram$'s. Find their present ages (in $\text{years}$).