$A$ father's age is three times the sum of the ages of his two children,but $20 \, \text{years}$ hence his age will be equal to the sum of their ages. Then,the father's age is (in $\text{years}$)

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?

One $year$ ago,a father was four times as old as his son. In $6$ $years$ time,his age will exceed twice his son's age by $9$ $years$. The ratio of their present ages is:

The ratio between the present age of Manisha and Deepali is $5:x$. Manisha is $9$ years younger than Parineeta. Parineeta's age after $9$ years will be $33$ years. The difference between Deepali's and Manisha's age is the same as the present age of Parineeta. What will come in place of $x$?

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 $5 \text{ years}$?

$7$ 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):