The students in three classes are in the ratio $4:6:9$. If $12$ students are increased in each class,the ratio changes to $7:9:12$. Then the total number of students in the three classes before the increase is

The ratio of the present age of Manoj to that of Wasim is $3:11$. Wasim is $12 \text{ yr}$ younger than Rehana. Rehana's age after $7 \text{ yr}$ will be $85 \text{ yr}$. What is the present age (in $\text{yr}$) of Manoj's father,who is $25 \text{ yr}$ older than Manoj?

The ratio of three numbers is $3:6:8$. If their product is $9216$,then what is the sum of the three numbers?

If $4 \, \text{years}$ ago the ratio between the ages of $P$ and $Q$ was $5:6$ and the sum of their ages at present is $52 \, \text{years}$, what is the ratio of their present ages?

The mean proportional of $0.25$ and $0.04$ is

What must be added to each term of the ratio $2:5$ so that it may equal to $5:6$?