Question

The inner diameter of a well is 2.5 m and it is 8 m deep. What would be the cost of cementing its inner wall at a rate of Rs. 350 per $m^2$ ?

• A. Rs.20000
• B. Rs.56000
• C. Rs.27000
• D. Rs.22000

Answer 1

The correct option is D

Rs.22000

Diameter of well (d) = 2.5 m

Radius of well (r) = $\frac{d}{2}$

=$\frac{2.5}{2}m$

=1.25 m

Height of well (h) = 8 m

Rate = Rs. 350 per $m^2$

Cost of cementing = ?

A well is cylinderical in shape. Hence Inner area of well = $2\pi rh$

$=2\times \frac{22}{7}\times 1.25\times 8$

$=\frac{440}{7}{m}^2$

$=\frac{440}{7}\times 350$

Rs.22000

Hence the cost of cementing the well on the inside = Rs. 22000