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 salaries of $A, B, C$ are in the ratio $2: 3: 5$. If increments of $15\%, 10\%,$ and $20\%$ are allowed respectively in their salaries,then what will be the new ratio of their salaries?

Three vessels having volumes in the ratio of $2: 3: 5$ are full of a mixture of water and milk. In the first vessel,the ratio of water and milk is $1: 3$,in the second $2: 3$,and in the third vessel,$2: 5$. If all the three vessels are poured into a large container,what is the resulting ratio of milk and water?

$Rs. 366$ are divided among $A, B$ and $C$ such that $A$ gets $\frac{1}{2}$ as much as $B$ and $C$ together,and $B$ gets $\frac{2}{3}$ as much as $A$ and $C$ together. What is the share of $A$ (in $Rs.$)?

If $P: Q = 8: 15$ and $Q: R = 3: 2$,then find $P: Q: R$.

The ratio of the number of boys and girls in a school of $720$ students is $7: 5$. How many more girls should be admitted to make the ratio $1: 1$?