One hundred thousand pounds per hour of water are to pass through a heat exchanger, which is to raise the water temperature from 140 to 200°F. Combustion products having a specific heat of 0.24 Btu/lb_m °F are available at 800°F. The overall heat-transfer coefficient is 12 Btu/h ft² °F. If 100,000 lb_m/h of the combustion products are available, determine a. the exit temperature of the flue gas b. the required heat-transfer area for a counter flow exchanger.