Question

A well of radius 7 m is dug 8m deep.the earth taken out of it is evenly spread all around it to a width of 21 m to form embankment .what is the hieght of the embarkment

Answer 1

radius of inside tank = 7m = 
height = 8 m = 
volume = 1231 m^3
outer radius = 7+21
= 28 m
area of embankment = area of outer circle - area of inner circle 
= 2310 m^2
height of embankment = volume/area
=1231/2310
=53.3 cm