The barrel of a fountain pen,cylindrical in shape,is $7 \, cm$ long and $5 \, mm$ in diameter. $A$ full barrel of ink in the pen is used up on writing $3300$ words on an average. How many words can be written in a bottle of ink containing one-fifth of a litre?

Selvi's house has an overhead tank in the shape of a cylinder. This is filled by pumping water from a sump (an underground tank) which is in the shape of a cuboid. The sump has dimensions $1.57 \, m \times 1.44 \, m \times 95 \, cm$. The overhead tank has a radius of $60 \, cm$ and a height of $95 \, cm$. Find the height of the water left in the sump after the overhead tank has been completely filled with water from the sump which had been full. Compare the capacity of the tank with that of the sump. (Use $\pi = 3.14$)

The volume of a cylinder with radius and height both $5 \, cm$ is $\ldots \ldots \ldots \pi \, cm^{3}$.

Twelve solid spheres of the same size are made by melting a solid metallic cylinder of base diameter $2 \, cm$ and height $16 \, cm$. The diameter of each sphere is (in $cm$):

The volume of a sphere with radius $1.5 \text{ cm}$ is $\ldots \ldots \ldots \text{ cm}^3$.

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