Air at 1 atm, 15C, and 60 percent relative humidity is first heated to 20C in a

Question:

Air at 1 atm, 15°C, and 60 percent relative humidity is first heated to 20°C in a heating section and then humidified by introducing water vapor. The air leaves the humidifying section at 25°C and 65 percent relative humidity. Determine
(a) The amount of steam added to the air, and
(b) The amount of heat transfer to the air in the heating section.