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

₹ $864$ is divided among $A, B$ and $C$ such that $8$ times $A$'s share is equal to $12$ times $B$'s share and also equal to $6$ times $C$'s share. How much (in ₹) did $B$ get?

$Rs. 366$ are divided among $A, B$ and $C$ such that $A$ gets $\frac{1}{2}$ as much as $B$ and $C$ together,and $B$ gets $\frac{2}{3}$ as much as $A$ and $C$ together. What is the share of $A$ (in $Rs.$)?

If $2: x :: 5: 7$,then $x$ is equal to

Two numbers are in the ratio of $5: 8$. If $12$ is added to each,they are in the ratio of $3: 4$. Find the sum of the two numbers.

$P$ varies inversely with the product of $Q$ and $R$. When $Q = 6$ and $R = 12$,$P = 75$. When $Q = 5$ and $R = 10$,what is the value of $P$?