Question

A well dug 20 m deep and it has a diameter 7 m. The earth which is so dug out is spread evenly on a rectangular plot 22 m long and 14 m broad. What is the height of platform formed?

Answer 1

Lets 1st find the volume of the mud dug out. Formula used will be $\pi$r²h.

Hence we have volume = 22/7 × (7/2)² × 20

We also have the volume of the cuboid at L x B x H
Here L = 22 and B = 14, we need to find H

Since the two volumes are equal, we have
22 x 14 x H = 22/7 × (7/2)² × 20

Hence we get the Height of the platform as 2.5m

Answer 2

Solution:-
Diameter = 7 m  so, radius = 3.5 m
H = 20 m
Volume of the earth dug out = π r² h
= 22/7 × 3.5 × 3.5 × 20
= 770 m³
Area of the platform = Length × breadth
⇒ 22 × 14 = 308 m²
Height of the platform = Volume of the earth dug out/area of the platform
⇒ 770/308
Height of the platform = 2.5 m Answer.