It costs $Rs. 2200$ to paint the inner curved surface of a cylindrical vessel $10 \, m$ deep. If the cost of painting is at the rate of $Rs. 20$ per $m^2$, find the radius of the base. (in $m$)

$A$ metal pipe is $77 \, cm$ long. The inner diameter of a cross section is $4 \, cm$ and the outer diameter is $4.4 \, cm$ (see Fig.). Find its total surface area. (in $, cm^2$)

The inner diameter of a circular well is $3.5 \, m$. It is $10 \, m$ deep. Find its inner curved surface area. [Assume $\pi = \frac{22}{7}$] (in $, m^2$)

The height of a cone is $16 \, cm$ and its base radius is $12 \, cm$. Find the curved surface area and the total surface area of the cone (Use $\pi = 3.14$). (in $, cm^2$)

The front compound wall of a house is decorated by wooden spheres of diameter $21 \, cm,$ placed on small supports as shown in the figure. Eight such spheres are used for this purpose,and are to be painted silver. Each support is a cylinder of radius $1.5 \, cm$ and height $7 \, cm$ and is to be painted black. Find the cost of paint required if silver paint costs $25$ paise per $cm^2$ and black paint costs $5$ paise per $cm^2$.

Find the amount of water displaced by a solid spherical ball of diameter $28 \, cm$.