The air in a room 15 ft by 12 ft by 12 ft is 4% carbon monoxide. Starting at t=0, fresh air containing no carbon monoxide is blown into the room at a rate of 300 ft³/min. If air in the room flows out through a vent at the same rate, when will the air in the room be 0.01% carbon monoxide? The air in the room will be 0.01% carbon monoxide after minutes. (Round to two decimal places as needed.)