If the base radius of a cone is increased by $20 \%$ and its slant height is doubled,then by what percentage will the area of its curved surface increase?

The curved surface area of a cylindrical well is $264 \, m^2$ and its volume is $924 \, m^3$. What are the diameter and the depth of the well? (in $m$)

$3$ cubes of metal whose edges are in the ratio $3: 4: 5$ are melted into a single cube,the length of whose diagonal is $48 \sqrt{3} \text{ m}$. Calculate the edges of the three cubes.

$A$ rectangular tin sheet is $12 \, cm$ long and $5 \, cm$ broad. It is rolled along its length to form a cylinder by making the opposite edges just touch each other. Then the volume of the cylinder is

The curved surface area of a hemisphere is $27.72 \text{ cm}^2$ and its volume is $19.404 \text{ cm}^3$. Find its radius in $\text{cm}$.

$A$ 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 $cm$):