Slab building boards contain 17% moisture by weight. They are dried to a water content of % by weight by circulating hot air over them. The fresh air contains 0.017 of moisture per pound of dry air....

Slab building boards contain 17% moisture by weight. They are dried to a water content of % by weight by circulating hot air over them. The fresh air contains 0.017 of moisture per pound of dry air. The exhaust air contains 0.075 of moisture per pound of dry air. How many cubic feet of fresh air at standard conditions must be used per ton of the building boards?