Find the $4^{th}$ proportional to $4, 16$ and $7$.

The respective ratio between the speeds of a car,a jeep,and a tractor is $3:5:2$. The speed of the jeep is $250\%$ of the speed of the tractor,which covers $360 \text{ km}$ in $12 \text{ hours}$. What is the average speed of the car and the jeep together in $\text{km/h}$?

If $50$ fewer candidates had applied and $25$ fewer had been selected,the ratio of selected to unselected candidates would have been $9:4$. How many candidates had applied if the initial ratio of selected to unselected candidates was $2:1$?

Two numbers are such that the ratio between them is $4:7$. If each is increased by $4$,the ratio becomes $3:5$. The larger number is:

Find the fraction which bears the same ratio to $\frac{1}{27}$ that $\frac{3}{7}$ does to $\frac{5}{9}$.

If the annual income of $A$,$B$,and $C$ is in the ratio $1:3:7$ and the total annual income of $A$ and $C$ is $Rs. 800,000$,then the monthly salary of $B$ (in $Rs.$) is: (in $,000$)