$A$ well with radius $2 \, m$ and depth $50 \, m$ is dug and the soil taken out is spread evenly on a circular plot with radius $40 \, m$. Find the increase in the level of the plot in $cm$.

$A$ cylindrical pencil sharpened at one edge is the combination of

$A$ metallic sphere with diameter $12 \, cm$ is melted and identical balls with radius $0.3 \, cm$ are produced. Find the number of balls produced.

$A$ cylinder with radius $8 \, cm$ and height $9 \, cm$ is surmounted by a cone of height $15 \, cm$. Find the total surface area and the volume of the combined solid.

$A$ factory manufactures $120000$ pencils daily. The pencils are cylindrical in shape,each of length $25 \,cm$ and circumference of base $1.5 \,cm$. Determine the cost of colouring the curved surfaces of the pencils manufactured in one day at $\operatorname{Rs.} 0.05$ per $dm^2$ (in $Rs.$).

The radii of a frustum of a cone are $28 \, cm$ and $7 \, cm$ and its height is $72 \, cm$. Find its curved surface area,total surface area,and volume.