$A$ hemispherical bowl made of brass has an inner diameter of $10.5 \, cm$. Find the cost of tin-plating it on the inside at the rate of $Rs. 16$ per $100 \, cm^2$.

$A$ village,having a population of $4000$,requires $150$ litres of water per head per day. It has a tank measuring $20 \,m \times 15 \,m \times 6 \,m$. For how many days will the water of this tank last?

In the figure,you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of $20 \, cm$ and a height of $30 \, cm$. $A$ margin of $2.5 \, cm$ is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade. $\left[ \text{Assume } \pi = \frac{22}{7} \right]$ (in $, cm^2$)

$A$ godown measures $60 \,m \times 25 \,m \times 15 \,m$. Find the maximum number of wooden crates each measuring $1.5 \,m \times 1.25 \,m \times 0.5 \,m$ that can be stored in the godown.

The capacity of a cuboidal water tank is $60,000$ litres. If its length is $5$ m and breadth is $4$ m, find its height in meters.

Find the curved surface area and the total surface area of a hemisphere with a radius of $2.1 \, m$.