please help with number 2 step by step

2. A tunnel dryer is to be used to dry 30 lb/h of raw cotton (dry basis) with a countercurrent flow of 1,800 lb/h of air (dry basis). Cotton enters at 70F with a moisture content of 100% (dry basis) and exits at 150F with 10% moisture (dry basis), and air enters at 200F and 1 atm with a relative humidity of 10%. The specific heat of dry cotton can be taken constant at 0.35 Btu/lb-'F. Calculate: a) rate of evaporation of moisture; [6marks] b) outlet temperature of the air; [10marks] c) rate of heat transfer. [4marks]