Hydrogen (H2) is burned with 100 percent excess air that enters the combustion chamber at 80oF, 14.5

Question:

Hydrogen (H2) is burned with 100 percent excess air that enters the combustion chamber at 80oF, 14.5 psia, and 60 percent relative humidity. Assuming complete combustion, determine
(a) The air-fuel ratio
(b) The volume flow rate of air required to burn the hydrogen at a rate of 40 lbm/h.