A 30L digester bioreactor is charged with media and 3.75L of cow dung. The reactor produces 5L of biogas per one liter of cow dung at a pressure of 1 atm and a temperature of 27oC. The biogas leaving the digester is saturated with water. On a dry basis, this gas contains 80 mol% methane and 20 mol% carbon dioxide. The gas is then fed to a furnace with 7 mols of dry air and undergoes complete combustion and complete conversion. Determine the composition of the resulting gas. Assume ideal gases.