One kg of saturated rigid-vapour mixture of water at 150 kPa (u_f = 467 kJ/kg, V_f = 0.001053 m³/kg ; u_g = 2520 kJ/kg and V_g = 1.159 m³/kg) with quality of 0.7 is enclosed in a piston-cylinder assembly. Heat is added at constant pressure to this system while a paddle wheel transfers a work of 50 kJ. The mixture eventually attains a saturated vapor state. The amount of heat added to the mixture (in kJ) is