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 $1: 1$?

Two numbers are in the ratio $3: 5$. If $9$ is subtracted from each,then the new numbers are in the ratio $12: 23$. The smaller number is:

An alloy of copper and zinc is taken in the ratio $1: 2$,and another alloy of the same metals is taken in the ratio of $2: 3$. How many parts of the two alloys must be taken to obtain a new alloy consisting of copper and zinc that are in the ratio $3: 5$?

Ajay,Aman,Suman,and Geeta rented a house and agreed to share the rent as follows:
Ajay:Aman $= 8: 15$,Aman:Suman $= 5: 8$,and Suman:Geeta $= 4: 5$. The part of the rent paid by Suman will be

The sum of two numbers is equal to $25$ and their difference is $20$. The ratio of the two numbers is

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 $50\%$ of the total girls and $40\%$ of the total boys. In the $HR$ discipline,there are $30\%$ of the total girls and $30\%$ of the total boys. In the Finance discipline,there are $20\%$ of the total girls and $30\%$ of the total boys. $7$ 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 enrolled in all three disciplines. What is the ratio of boys to girls only in the Marketing discipline?