In a school,there were $1554$ students and the ratio of the number of boys to girls was $4:3$. After a few days,$30$ girls joined the school but some boys left; as a result,the ratio of boys to girls became $7:6$. The number of boys who left the school is:

An amount of $Rs. 2430$ is divided among $A$,$B$,and $C$ such that if their shares are reduced by $Rs. 5$,$Rs. 10$,and $Rs. 15$ respectively,the remainders are in the ratio of $3:4:5$. Then,$B$'s share was (in $Rs.$):

The ratio of incomes of $P$ and $Q$ is $3:4$ and the ratio of their expenditures is $2:3$. If at the end of the year,each saves ₹ $2000$,then the income of $P$ is (in ₹):

Two numbers are in the ratio $2:3$. If $2$ is subtracted from the first and $2$ is added to the second,the ratio becomes $1:2$. The sum of the numbers is:

If $a-b : b-c : c-d = 1 : 2 : 3$,then what is the value of $(a+d) : c$?

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,namely,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 the $HR$ and Marketing both. $6$ boys and $7$ girls are in the $HR$ and Finance both. $5$ boys and $8$ girls are in the Marketing and Finance both. $2$ boys and $3$ girls are enrolled in all the three disciplines. What percentage of students are enrolled in all three disciplines?