Q43 of 107 Page 16

A well of diameter 3 m is dug 14 m deep. The earth taken out of it has been spread evenly all around it to a width of 4 m to form an embankment. Find the height of the embankment.

Let the height of the embankment be ‘h’ m


Radius of well


=1.5 m


Height of the well =14m



Volume of earth dug out (volume of cylinder)



=99 m3


Outer Radius of the embankment(R) =1.5 m + 4 m


=5.5 m


Inner radius of the embankment(r) =1.5 m


Volume of embankment =Volume of earth dug out


Volume of embankment



= 27.5πh


Volume of embankment =Volume of earth dug out


⇒ 27.5h = 99



⇒ h = 9/8 = 1.125 m


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