Question

A well of inner diameter $14m$ is dug to a depth of $12km.$ Earth taken out of it has been evenly spread all around it to a width of $7m$ to form an embankment. Find the height of the embankment so formed.

Answer 1

Given

Width of embankment $=7m$

Inner radius $r=7m$

Outer radius $R=7+7=14m$

Volume of earth dug out = Volume of soil embankment

$\pi r^{2}H=\pi h(R^2-r^2)$

$7^2\times 12000=h({14}^2-7^2)$

$588000=h\times 147$

$h=\frac{588000}{147}$

$h=4000m$

Hence, height of the embankment is 4000m.