500 persons have to dip in a rectangular tank which is 80 m long and 50 m broad. What is the rise in the level of water in the tank, if the average displacement of water by a person is `0. 04\ m^3` ?

Explanation

Let the rise of water level in the pond be hm, when 500 person are taking a dip into a cubiodal pond.
Given that, Length of the cuboidal pond = 80 cm
Breadth of the cuboidal pond = 50 m

Now, volume for the rise of water level in the pond = `"Lenght" xx "Breadth" xx "Height"`
`= 80 xx 50 xx h= 4000 hm^(3)`
and the average displacement of the water by a person ` = 0.04m ^(3)`
So, the average displacement of the water by 500 person `= 500 xx 0.04m^(3)`ltbr. Now by given condititon,
volume for the rise of water level in the pond = Average displacement of the water by 500 persons
`rArr" "400 h = 500 xx 0.04`
`therefore" " h = (500 xx 0.04)/(4000) = (20)/(4000) = (1)/(200)m`
`" "= 0.005 m`
`" "= 0.005xx 100 cm `
`" " = 0.5 cm`
Hence, the required rise of water level in the pond is 0.5 c