Using the volume of the spherical balloon, it is found that it will take 24 hours for the balloon to become completely empty.
<h3>What is the volume of a sphere?</h3>
The volume of a sphere of radius r is given by:

Aspherical balloon has a radius of 6 feet, hence the volume is:

It has already lost 20% of it's air, and air is leaking out of the balloon at a rate of 30 cubic feet per minute, hence the volume after t minutes is given by:


It will be completely empty when:





Rounding, it will take 24 hours for the balloon to become completely empty.
More can be learned about the volume of a sphere at brainly.com/question/25608353