A direct-heat, countercurrent flow, rotary dryer with a 6-ft diameter and 60 ft length is available to dry titanium dioxide particles at 70 deg F and 1 atm with a moisture content of 30% (dry basis) to a moisture content of 2% (dry basis) at 100 deg F. Hot air entering through the cross section of the dryer is available at 400 deg F with a humidity of 0.015 lb/lb dry air. Experiments show that an air- mass velocity of 500 lb/hr.ft^2 will not cause serious dusting. The specific heat of solid titanium dioxide is 0.165 BTU/ lb. deg F and the density of the wet solid is 240 lb/ft^3. Assume no heat losses during drying and that the rotary dryer is constantly filled with wet titanium dioxide particles up to one tenth of the total drum volume. Determine (a) the outlet humidity of air (b) production rate in lb/hr titanium dioxide (c) outlet temperature of air. Are the values reasonable? If not, explain.