Question

A water tank has a square base with each side of length 4 meters. water enters through a hose at a constant rate of 20 liters per minute. at the same time a valve in the bottom is opening, so that after t minutes, water leaves at a rate of t liters per minute. if the tank starts out filled to a depth of 5 meters, after how many minutes will the tank be empty?

Answer 1

43.66 minutes

4^2*5+20*x-x^2/2=0
Or
Initial volume of water plus rate of water in minus rate of water out