If $0.75 : x :: 5 : 8,$ then $x$ is equal to

If $Rs. 782$ is divided into three parts proportional to $\frac{1}{2}: \frac{2}{3}: \frac{3}{4}$,then the first part is (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?

Find the number which,when subtracted from the terms of the ratio $12: 17$,makes it equal to the ratio $2: 3$.

What number should be added to or subtracted from each term of the ratio $17: 24,$ so that it becomes equal to $1: 2?$

The ratio of the earnings of $A$ and $B$ is $4 : 7$. If the earnings of $A$ increase by $50\%$ and those of $B$ decrease by $25\%$,the new ratio of their earnings becomes $8 : 7$. What are $A$'s earnings?