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

Radius of well (r) = 3/2 m, Depth of well h₁ = 14 m, Width of embankment = 14 m
The embankment is in the form of hollow cylinder with internal radius r₂ = 3/2 m and Outer radius r₁ = 3/2 + 4 = 11/2 m
Let the height of embankment = H
According to question, the earth dug out from the well = volume of embankment
⇒ πr₁² = π (r₁² – r₂² )h
⇒ π(3/2)² 14 = π [(11/2)² – (3/2)²] × h ⇒ 9/4 14 = 112/4h ⇒ h = 9/8 = 1.125m
Hence, the height of embankment is 1.125 m.