$A$ well with $14\, m$ inside diameter is dug $50\, m$ deep. Earth taken out of it is spread all around a rectangular field of length $110\, m$ and width $100\, m$. Find the increase in the height of the field (in $cm$).

$A$ small village, having a population of $5000$, requires $130\, \text{litres}$ of water per head per day. The village has an overhead cuboidal tank measuring $20\, \text{m} \times 13\, \text{m} \times 10\, \text{m}$. For how many days will the water of this tank last?

Find the total surface area of a cone with diameter $6\, cm$ and slant height $11\, cm$. (in $cm^2$)

Metal spheres,each of radius $2 \, cm$,are packed into a rectangular box of internal dimensions $16 \, cm \times 8 \, cm \times 8 \, cm$. When $16$ spheres are packed,the box is filled with preservative liquid. Find the volume of this liquid. Give your answer to the nearest integer. [Use $\pi = 3.14$] (in $cm^3$)

$A$ sphere and a right circular cylinder of the same radius have equal volumes. By what percentage does the diameter of the cylinder exceed its height?

Curved surface area of a cone $= \dots$