Question

The radius of the base of a cylindrical column of a building is 25 cm and its height is 3.5 m. It costs Rs 15.50 per sq m to paint this column. What will it cost to paint 10 such columns?

Answer 1

Radius of cylinder (r) = 25cm = 0.25m (1 m =100 cm)
Height of cylinder (h) = 3.5m
Curved surface area of cylinder = 2πrh
$$\begin{gathered} =2\times \frac{22}{7}\times 0.25\times 3.5 \\ =5.5\mathrm{sq}\mathrm{m} \end{gathered}$$
Cost of painting 1 sq m = Rs.15.50
Cost of painting 38.5 sq m = Rs.15.50 × 5.5 = Rs. 85.25
Cost of painting 10 such columns = Rs. 85.25 × 10 = Rs. 852.5