In a mixture of $60 \, \text{litres}$,the ratio of milk and water is $2:1$. What amount of water (in $\text{litres}$) must be added to make the ratio of milk and water $1:2$?

$A$ and $B$ have their monthly incomes in the ratio $8: 5,$ while their monthly expenditures are in the ratio $5: 3.$ If they save ₹ $12,000$ and ₹ $10,000$ monthly respectively,then the difference in their monthly incomes is (in ₹): (in $,000$)

What will be the inverse ratio of $17: 19$?

In a college, $150$ students of $MBA$ are enrolled. The ratio of boys to girls is $7:8$. There are three disciplines: Marketing, $HR$, and Finance. In Marketing, $50\%$ of the girls and $40\%$ of the boys are enrolled. In $HR$, $30\%$ of the girls and $30\%$ of the boys are enrolled. In Finance, $20\%$ of the girls and $30\%$ of the boys are enrolled. $7$ boys and $9$ girls are in both $HR$ and Marketing. $6$ boys and $7$ girls are in both $HR$ and Finance. $5$ boys and $8$ girls are in both Marketing and Finance. $2$ boys and $3$ girls are in all three disciplines. Find the ratio of the number of boys in both Marketing and Finance to the number of girls only in Finance.

If $33 \%$ of $A$ is equal to $55 \%$ of $B$,then find the ratio of $A$ and $B$.

In an army selection process,the ratio of selected to unselected candidates was $5:1$. If $100$ fewer candidates had applied and $20$ fewer had been selected,the ratio of selected to unselected candidates would have been $6:1$. How many candidates had applied for the process?