1. The problem statement, all variables and given/known data A solid fuel supplied to a furnace had the following composition by mass. Carbon: 86% Hydrogen: 5% Oxygen:4% Incombustibles: 5% Dry volumetric analysis of the combustion products showed the flue gas contained 15% and 1.5% of CO2 and CO respectively. The test on the ashes discharged from the furnace found 0.01 kg of un-burnt carbon per kilogram of the fuel supplied to the furnace. Determine the air/fuel ratio by mass. ANSWER is 12.67 if this helps 2. The attempt at a solution So firstly I write out the combustion equation: (0.86/12)C + (0.05/2)H2 + (0.06/32)O2 + 0.05ASH + Y(02 + 3.76 N2) = aCO2 + bH20 + d02 + fN2 + 0.05ASH Firstly is the combustion equation correct? When I equate the element atoms I have too many variables missing: a=(0.86/12) b=(0.05/2) O: (0.06/32)×2 + 2Y = 2a + b + 2d N: (3.76Y)×2 = 2f How do I calculate the value of Y and what do I do with the 0.01 kg of un-burnt carbon? I would very much appreciate any help with this question. Thank you.