An axial flow compressor of 50% reaction blading has isentropic efficiency of 82%. It draws air at 170C and compresses in the pressure ratio of 4 : 1. The mean blade speed and flow velocity are constant throughout the compressor. The inlet and outlet angles of blades are 150 and 450 respectively (angles measured from axial direction). Blade speed = 180 m/s and work input factor = 0.84. Calculated (i) flow velocity and (ii) number of stages.