The length,breadth,and height of a room are $5\, m$,$4\, m$,and $3\, m$ respectively. Find the cost of whitewashing the walls of the room and the ceiling at the rate of $Rs. 7.50$ per $m^2$.

$A$ conical tent is $10 \, m$ high and the radius of its base is $24 \, m$. Find the cost of the canvas required to make the tent,if the cost of $1 \, m^2$ canvas is $Rs. 70$.

$A$ dome of a building is in the form of a hemisphere. From inside,it was white-washed at the cost of $Rs. 4989.60$. If the cost of white-washing is $Rs. 20$ per square metre,find the volume of the air inside the dome. (in $, m^3$)

At a Ramzan Mela,a stall keeper in one of the food stalls has a large cylindrical vessel of base radius $15 \, cm$ filled up to a height of $32 \, cm$ with orange juice. The juice is filled in small cylindrical glasses (see figure) of radius $3 \, cm$ up to a height of $8 \, cm$,and sold for $Rs. 15$ each. How much money does the stall keeper receive by selling the juice completely?

$A$ cylindrical pillar is $50 \, cm$ in diameter and $3.5 \, m$ in height. Find the cost of painting the curved surface of the pillar at the rate of $Rs. \, 12.50$ per $m^2$. $\left[ \text{Assume } \pi = \frac{22}{7} \right]$

Find the lateral or curved surface area of a closed cylindrical petrol storage tank that is $4.2\, m$ in diameter and $4.5\, m$ high. $\left[\text{Assume } \pi = \frac{22}{7}\right]$ (in $, m^2$)