The present ages of $A$ and $B$ are in the ratio $5:6$ respectively. After seven years,this ratio becomes $6:7$. Then the present age of $A$ in years is:

In a class there are $z$ students. Out of them $x$ are boys. What part of the class is composed of girls?

If $3A = 4B = 5C$,then $A : B : C$ is

When $X$ is subtracted from the numbers $9, 15$ and $27$,the remainders are in continued proportion. What is the value of $X$?

$Rs. 5625$ are divided among $A, B$ and $C$ such that $A$ receives half as much as $B$ and $C$ together,and $B$ receives one-fourth as much as $A$ and $C$ together. Find the sum of $A$'s and $B$'s share together (in $Rs.$).

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?