Flue gas enters a shell-and-tube exchanger at 3000 g/h and 130 °C and heats water (500 g/h) from 30 °C to 80 °C. Find the exit temperature of the flue gas (answer in °C). Assume c_{p,gas} = 0.5 J/g·°C and c_{p,water} = 4.2 J/g·°C.