Q : 7    The inner diameter of a circular well is \small 3.5\hspace{1mm}m. It is \small 10\hspace{1mm}m deep. Find

            (ii) the cost of plastering this curved surface at the rate of Rs 40 per \small m^2.

Answers (1)
H Harsh Kankaria


Inner diameter of the circular well =  d = \small 3.5\hspace{1mm}m

Depth of the well = h = 10\ m

\therefore The inner curved surface area of the circular well is 110\ m^2

Now, the cost of plastering the curved surface per \small m^2 = Rs. 40

\therefore Cost of plastering the curved surface of  110\ m^2 = Rs.\ (110 \times 40) = Rs.\ 4400

Therefore, the cost of plastering the well is Rs.\ 4400