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

Radius of well (r) = 7/2m, Height of well = 20 m
Lenght of platfrom = 22 m, Width of platform = 14 m
Let the height of the platform = H
According to Question, volume of the earth dug out = Volume of earth of platform
πr²h = 22 × 14 × H
⇒ 22/7 × (7/2)² × 20 = 22 × 14 × H
⇒ 11 × 7 × 10 = 22 × 14 × H
⇒ (11 × 7 × 10/22 × 14) = H ⇒ H = 2.5 m
Hence, the height of the platform is 2.5 m.