$P$ 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 $P$?

An employer reduces the number of his employees in the ratio $9:7$ and increases their wages in the ratio $14:15$. Find the ratio in which the total bill of wages increases or decreases.

The ratio of the ages of a man and his wife is $4:3$. After $4$ years,this ratio will be $9:7$. If at the time of marriage,the ratio was $5:3$,then how many years ago were they married?

₹ $900$ is divided among $A, B, C$; the division is such that $\frac{1}{2}$ of $A$'s money $= \frac{1}{3}$ of $B$'s money $= \frac{1}{4}$ of $C$'s money. Find the amount received by $A, B,$ and $C$.

If $\frac{5a+3b}{2a-3b} = \frac{23}{5}$,then the value of $a:b$ is:

If $24$ is deducted from $45 \%$ of a number,the result becomes $48$. What will be $\frac{3}{8}$ part of that number?