The ratio between the present ages of $P$ and $Q$ is $6:7$. If $Q$ is $4 \text{ years}$ older than $P$,what will be the ratio of the ages of $P$ and $Q$ after $4 \text{ years}$?

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 $\text{years}$)

$3 \text{ years}$ ago,the average age of a family of $5$ members was $17 \text{ years}$. $A$ baby having been born,the average age of the family is the same today. What is the age of the child? (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 $\text{years}$)

Three times the present age of a father is equal to eight times the present age of his son. $8$ years hence,the father will be twice as old as his son at that time. What are their present ages?

$5 \, \text{years}$ ago, Mr. Sohanlal was thrice as old as his son, and $10 \, \text{years}$ hence, he will be twice as old as his son. Mr. Sohanlal's present age (in $\text{years}$) is: