You own a mechanically ventilated swine facility. the dry bulb temperature inside the facility is 50 degrees f and outside is only 30 degrees f. inside you have a relative humidity of 70% and outside the relative humidity is 20%. to keep the humidity from getting any higher you need to remove 12 gallons of water per hour from the facility with the ventilation air. at what rate (cfm) must the fans pull inside air out of the building?