Hot oil (cp = 1.9 kJ/kg-K) at a temperature of 180°C and a flow rate of 0.4 kg/s enters a 1-shell- pass and 6-tube-pass heat exchanger. The oil is cooled by water (cp= 4.184 kJ/kg-K) entering the heat exchanger at 25°C and at a flow rate of 0.3 kg/s. The overall heat transfer coefficient of the heat exchanger is 350 W/m².K. The length of each tube pass in the heat exchanger is 5m. If the effectiveness of the heat exchanger is estimated to be 0.5, determine the diameter of the thin walled tubes used in the heat exchanger and the outlet temperatures of water.