Question

A 20m deep well having diameter 7m is dug and the earth dug out is evenly spread to form a platform 22m by 14m. Find the height of the platform.

• A. 5.0 m
• B. 2.81 m
• C. 3.95 m
• D. 2.5 m

Answer 1

The correct option is D

2.5 m

Let h be the height of the platform

Volume of the cylinder = $\pi r^{2}h=\frac{22}{7}\times (3.5{)}^2\times 20=770m^3$

Volume of a cuboid = l × b × h = 22 × 14 × h = 308h

Volume of cylinder = volume of cuboid

770 = 308h $⟹$ h = 2.5 m

Height of platform = 2.5m