Question

A well is to be dug $20$ m deep, $2.25$ m inside diameter, with a brick lining of $0.35$ m thickness. What are the quantities of brickwork?

• A. $14.75$ $m^3$
• B. $57.2$ $m^3$
• C. $136$ $m^3$
• D. $572$ $m^3$

Answer 1

The correct option is B $57.2$ $m^3$

$h=20$m, Inner radius, $r=\frac{2.25}{2}=1.125m$

Brick work thickness $=0.35$m

Outer radius, $R=r+0.35m=1.475$m

$\therefore$ Volume of brick work $=\pi (R+r)\times 0.35\times 20$

$=\frac{22}{7}(1.475+1.125)\times 7$

$=22\times 2.6=57.2m^3$