In a counter-flow heat exchanger for the hot fluid, the heat capacity = 214/kg k, mass flow rate = 5 kg/s, inlet temperature = 150°C, outlet temperature = 100°C. For the cold fluid, heat capacity = 4...

In a counter-flow heat exchanger for the hot fluid, the heat capacity = 214/kg k, mass flow rate = 5 kg/s, inlet temperature = 150°C, outlet temperature = 100°C. For the cold fluid, heat capacity = 4 kJ/kg k, mass flow rate = 10 kg/s, inlet temperature = 20°C. Neglecting heat transfer to the surroundings, the outlet temperature of cold fluid is—

(a) 7.5                   (c) 45.5

(b) 32.5                 (d) 70