A water tank has a square base of area 4 square meters. Initially the tank contains 30 cubic meters. Water leaves the tank, starting at t=0, at the...

A water tank has a square base of area 4 square meters. Initially the tank contains 30 cubic meters. Water leaves the tank, starting at t=0, at the rate of 2 + 4 t cubic meters per hour. Here t is the time in hours. What is the depth of water remaining in the tank after 3 hours?