Hot water enters a well-insulated mixer at 80°C at a mass flow rate of 0.5 kg/s and cold water enters the mixer at 20°C and if the water exits the mixer at 41°C. Cp = 4.18 kJ/kg K.

a) 39.5 kJ/kg
b) 15.6 kJ/kg
c) 6.22 kJ/kg
d) 20.9 kJ/kg