The ratio of the age of Tina and Rakesh is $9:10$. $10 \text{ years}$ ago,the ratio of their ages was $4:5$. What is the present age of Rakesh (in $\text{years}$)?

The ratio of the present ages of $A$ and $B$ is $7:9$. $6$ years ago,the ratio of $\frac{1}{3}$ of $A$'s age at that time and $\frac{1}{3}$ of $B$'s age at that time was $1:2$. What will be the ratio of $A$'s to $B$'s age $6$ years from now?

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 sum of the ages of two brothers, having a difference of $8 \, \text{years}$ between them, will double after $10 \, \text{years}$. What is the ratio of the age of the younger brother to that of the elder brother?

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?

The present ages of Vishal and Shekhar are in the ratio of $14: 17$. $6 \, \text{years}$ from now,their ages will be in the ratio of $17: 20$. What is Shekhar's present age (in $\text{years}$)?