Coal as fired, contains 2.5% moisture. On the dry basis the coal analysis is as follows: carbon -80%, hydrogen- 6%, oxygen-8%, ash- 6%. The flue gas analysis. The few gas analysis shows as carbon dioxide 14%, carbon monoxide 0.4%, oxygen 5.6% and nitrogen 80%. The air used has a dew point of 50°F. The barometer shows 29.9 inches of mercury. Calculate the dew point of the stack gas.