Air flows into a convergent-divergent nozzle with an exit area of1.59 times the throat area of 0.005

Question:

Air flows into a convergent-divergent nozzle with an exit area of1.59 times the throat area of 0.005 m. The inlet stagnation state is 1 MPa, 600 K. Find the backpressure that will cause subsonic flow throughout the entire nozzle with M = 1 at the throat. What is the mass flow rate?