Estimate how much carbon (in pounds) must be purcahsed for a typical 2-bed carbon adsorption system to treat 5000 cfm of air at 95 degrees F and 1 atm. The air contains 600 ppm of styrene. A run time of at least 2 hours is desired before switching beds. Pilot plant tests have shown that styrene adsorbs well (steep breakthrough curve, 6 inch active adsorption zone), and that the working capacity is 12 g styrene/100 g carbon. The carbon has a bulk density of 30 lb/cubic foot. Making other appropriate assumptions as needed, also estimate the bed dimensions (in feet).