If the radius of a cylinder is doubled and the height is halved,then what would be the ratio between the new curved surface area and the previous curved surface area of the cylinder?

$A$ sphere is cut into two hemispheres. One of them is used as a bowl. It takes $8$ bowlfuls of this to fill a conical vessel of height $12\, cm$ and radius $6\, cm$. The radius of the sphere (in centimeter) will be

The base of a right prism is an equilateral triangle. If the lateral surface area and volume are $120 \, cm^2$ and $40 \sqrt{3} \, cm^3$,respectively,then the side of the base of the prism is ...... $cm$.

The capacity of a tank,in the form of a cylinder,is $6160 \, m^3$. If the diameter of its base is $28 \, m$,find out the cost of painting its inner curved surface at the rate of ₹ $2.8$ per $m^2$. (Use $\pi = \frac{22}{7}$)

$A$ conical cup is filled with ice cream. The ice cream forms a hemispherical shape on its open top. The radius of the hemispherical part is $7 \, cm$. The radius of the hemispherical part equals the height of the cone. Then the volume of the ice cream is $...... cm^3$. $\left[\pi=\frac{22}{7}\right]$

$A$ cylindrical tank of diameter $35 \, cm$ is full of water. If $11$ litres of water is drawn off,the water level in the tank will drop by (in $cm$):