A feedwater heater operates at steady state with liquid water entering at inlet 1 at 7 bar, 42oC, and a mass flow rate of 70 kg/s. A separate stream of water enters at inlet 2 as a two-phase liquid-vapor mixture at 7 bar with a quality of 98%. Saturated liquid at 7 bar exits the feedwater heater at 3. Ignoring heat transfer with the surroundings and neglecting kinetic and potential energy effects, determine the mass flow rate [in kg/s] at inlet?