Two equal glasses are respectively $\frac{1}{3}$ and $\frac{1}{4}$ full of milk. They are then filled up with water and the contents are mixed in a tumbler. Find the ratio of milk and water in the tumbler.

If in $30$ litre mixture of milk and water the ratio of milk and water is $7 : 3$, find out the quantity of water to mix in order to make this ratio $3 : 7$?

In a bag, there are coins of $25$ paise, $10$ paise and $5$ paise in the ratio $1 : 2 : 3$. If there are in all $Rs 30$, how many $5$ paise coins are there?

Shyam has a sister who is half of his age. When Shyam double, what will be the ratio of his age to his sister's age?

$25$ men with $10$ boys can do in $6$ days as much work as $21$ men with $30$ boys can do in $5$ days. How many boys must help $40$ men to do the same work in $4$ days?

A contractor took a contract for building $12$ kilometre road in $15$ days and empolyed $100$ labours on the work. After $9$ days he found that only $5$ kilometre road had been constructed. How many more labours should be employed to ensure that the work may be completed with in the given time?

What number has $5$ to $1$ ratio to the number $10$?