On a religious day, 50 men take a dip in a rectangular water tank that is 40 m long and 20 m wide. If each man displaces, on average, 4 m^3 of water, by how much does the water level in the tank rise?

Problem Restatement

Compute the rise in water level when a known total volume is added to a tank of known plan area.

Given data

• Number of men = 50
• Average displacement per man = 4 m^3
• Tank length = 40 m, breadth = 20 m → plan area A = 40 × 20 = 800 m^2

Concept / Formula

Rise in level = Added volume ÷ Plan area.

Step-by-step calculation

Total displaced volume = 50 × 4 = 200 m^3Rise, h = 200 ÷ 800 = 0.25 m = 25 cm

Final Answer

Water level rises by 25 cm.