$A$ 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 is closed at both the ends by $30 \, cm$ high cones. The radius of the cylinder is $21 \, cm$ and the total height of the solid is $140 \, cm$. Find the volume of this solid (in $cm^3$).

$CSA$ of a conical tank with height $3\,m$ and diameter $8\,m$ is $\ldots \ldots \ldots \ldots m^{2}$. $(\pi = 3.14)$

$A$ solid right circular cone of height $120 \,cm$ and radius $60 \,cm$ is placed in a right circular cylinder full of water of height $180 \,cm$ such that it touches the bottom. Find the volume of water left in the cylinder,if the radius of the cylinder is equal to the radius of the cone.

The earth dug out by digging a well with diameter $5.4 \, m$ and depth $20 \, m$ is uniformly spread on a circular ground with radius $15 \, m$. Find the increase in the level of the ground in $cm$.

$A$ cylinder with radius $14 \, cm$ is closed at one end by a $48 \, cm$ high cone and at the other end by a hemisphere. If the height of the cylinder is $22 \, cm$,find the total surface area of the article (in $cm^2$).