A fuel contains bituminous coal and water. The analysis of the dry coal is 74.41% C, 4.95% H 1.44% N. 1.35% S, 7.85%O and 10.0% non-combustible ash. The fuel is 3.8% by weight water. After the fuel is burned an Orsat analysis of the exiting flue gas reveals this composition: 10.62% CO2, 3.54% CO, 0.10% SO2, 6.33% O2, and 79.41 % N2. What is the percent excess air used to burn this fuel