Consider a finned-tube, cross-flow heat exchanger with both fluids unmixed. this heat exchanger is used to heat pressurized water with a flow rate of 1 kg/s from 35 to 125 c using exhaust gas. the exhaust gas enters the heat exchanger at 300 c and exits at 100 c. the overall heat transfer coefficient based on the gas-side area is uh=100 w/m2 .k. find the required gas-side heat transfer area, ah. use both ntu and lmtd methods and compare the results.