The floor of a rectangular hall has a perimeter of $250\, m$. If the cost of painting the four walls at the rate of $10$ per $m^2$ is $Rs. 15000$,find the height of the hall. (in $, m$)

Find the surface area of a sphere of radius $7 \, cm$. (in $, cm^{2}$)

$A$ river $3 \,m$ deep and $40 \,m$ wide is flowing at the rate of $2 \,km$ per hour. How much water will fall into the sea in a minute (in $,m^3$)?

In the figure,you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of $20 \, cm$ and a height of $30 \, cm$. $A$ margin of $2.5 \, cm$ is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade. $\left[ \text{Assume } \pi = \frac{22}{7} \right]$ (in $, cm^2$)

Find the volume of a sphere whose surface area is $154 \, cm^2$.

$A$ soft drink is available in two packs: $(i)$ a tin can with a rectangular base of length $5 \, cm$ and width $4 \, cm$ having a height of $15 \, cm$,and $(ii)$ a plastic cylinder with a circular base of diameter $7 \, cm$ and height $10 \, cm$. Which container has greater capacity and by how much (in $, cm^3$)?