Question

$500$ persons have to dip in a rectangular tank which is $80m$ long and $50m$ broad. What is the rise in the level of water in the tank, if the average displacement of water by a person is $0.04m^3$?

Answer 1

The volume of one person is $0.04m^3$ , because when the person takes a dip in the tank, the amount of water displaced is equal to the volume of the person.

$500$ people take dip at the same time, then water displaced is $500\times 0.04=20m^3$

The water rises inside the tank of the area of $80m\cdot 50m=4000m^2$

The height to which water rises $=\frac{volume}{area}=\frac{20}{4000}=\frac{1}{200}m=0.005m=5millimeters$