A bathtub is filled to the brim with water. It has a partially closed drain, so a plumber has set up a draining hose for the water to leave the tub. Water drains through the hose 4 times as fast as it drains through the clogged drain. Using both the drain and the hose, it takes the tub 8 minutes to empty completely. If the hose were removed, how long would it take the full tub to empty through the clogged drain?