500 persons are taking a dip in a cuboidal pond, which is 80 m long and 50 m broad. What is the rise in the water level in the pond, if the average displacement of the water by one person is 0.04 m³?

Correct option is A

Given:
Average displacement by one person = 0.04 m³
Length of the pond, l = 80 m
The breadth of pond, b = 50 m
The number of persons taking a dip in a cuboidal pond = 500.
Formula Used:

The volume of water raised in pond = l × b × h
Solution:
Average displacement by one person = 0.04 m
Average displacement by 500 persons = 500 × 0.04 = 20 m³
Hence, the volume of water raised in pond = 20 m³
Now,
The volume of water raised in pond = l × b × h
=> V = 80 × 50 × h => V = 4000 × h
=> 20 m³ = 4000 × h
=> h = 0.005 m
=> h = 0.005 × 100
=> h = 0.5 cm