A perfectly insulated double pipe heat exchanger is operating at steady state. Saturated steam enters the inner pipe at 100 °C and leaves as saturated water at 100 °C. Cooling water enters the outer pipe at 75 °C and exits at 95 °C. The overall heat transfer coefficient is 1 kW m^-2 K^-1 and the heat transfer area is 1 m² . The average specific heat capacity of water at constant pressure is 4.2 kJ kg^-1 K^-1 . The required cooling water flow rate is __________ kg s^-1 (rounded off to two decimal places).