There is $1000 \, \text{litres}$ of milk in a pot. $100 \, \text{litres}$ of milk is taken out and the same amount of water is poured into it. Again, $200 \, \text{litres}$ of the mixture is taken out and the same amount of water is poured into it, and finally, $400 \, \text{litres}$ of the mixture is taken out and the same amount of water is poured into it. What is the amount of milk in the resulting mixture?

The income of $A, B$ and $C$ are in the ratio $7: 9: 12$ and their spendings are in the ratio $8: 9: 15$. If $A$ saves $\frac{1}{4}$th of his income,then the savings of $A, B$ and $C$ are in the ratio of:

An employer reduces the number of his employees in the ratio $9: 8$ and increases their wages in the ratio $14: 15$. If the original wage bill was ₹ $18,900$,find the ratio in which the wage bill is decreased.

The fourth proportional to $5, 8, 15$ is

$A$ certain sum of money was divided between $A$,$B$,and $C$ in the ratio $5: 6: 9$. If $A$ received ₹ $450$,what was the total sum divided?

In a college,$150$ students of $MBA$ are enrolled. The ratio of boys to girls is $7:8$. There are three disciplines in the college: Marketing,$HR$,and Finance. In the Marketing discipline,there are $50\%$ girls of their total number and the boys are $40\%$ of their total number. In the $HR$ discipline,girls are $30\%$ of their total number while boys are $30\%$ of their total number. The Finance discipline has girls $20\%$ of their total number and the boys are $30\%$ of their total number. $7$ boys and $9$ girls are in $HR$ and Marketing both. $6$ boys and $7$ girls are in $HR$ and Finance both. $5$ boys and $8$ girls are in Marketing and Finance both. $2$ boys and $3$ girls are enrolled in all the three disciplines. By what percent is the number of boys in the Marketing discipline more than the number of girls in the $HR$ discipline?