$A$ school provides milk to the students daily in cylindrical glasses of diameter $7 \, cm$. If the glass is filled with milk up to a height of $12 \, cm$, find how many litres of milk is needed to serve $1600$ students.

The radii of two cylinders are in the ratio of $2:3$ and their heights are in the ratio of $5:3$. The ratio of their volumes is

It costs $Rs. 2200$ to paint the inner curved surface of a cylindrical vessel $10 \, m$ deep. If the cost of painting is at the rate of $Rs. 20$ per $m^2$, find the radius of the base. (in $m$)

$A$ metal sphere of radius $20\, cm$ is melted and then cast into small hemispheres each of radius $5\, cm$. Find the number of hemispheres thus obtained (in balls).

The water for a factory is stored in a hemispherical tank whose internal diameter is $14\, m$. The tank contains $50\, kilolitres$ of water. Water is pumped into the tank to fill it to its capacity. Calculate the volume of water pumped into the tank (in $m^3$).

Parveen wanted to make a temporary shelter for her car by making a box-like structure with tarpaulin that covers all the four sides and the top of the car (with the front face as a flap which can be rolled up). Assuming that the stitching margins are very small,and therefore negligible,how much tarpaulin would be required to make the shelter of height $2.5 \, m$,with base dimensions $4 \, m \times 3 \, m$ (in $m^2$)?