Question

A well of diameter 2 m is dug 14 m deep, The earth taken out of it is spread evenly all around it to form an embankment of height 40 cm. Find the width of the embankment.

Answer 1

Given,

Diameter of well $=2$ m

So, radius of well $r=1$m

Height $h=14$ m

Now, dimensions of embankment

Height $h_1=40cm=0.4m$

Let, Radius of embankment$=R$

Width of embankment $=R-r$

Vol. of earth dug out = vol of embankment

$=>\frac{22}{7}\times 1^2\times 14=\frac{22}{7}\times (R^2-1)\times 0.4$

$=>R^2-1=\frac{14}{0.4}$

$=>R^2-1=35$

$=>R^2=36$

$=>R=6$

Width of embankment

$=R-r$

$=6-1=5m$