A car driver spends 3 h driving at an average speed of 80 km/h, stops for 30min to have some rest, and then drives at an average speed of 90 km/h for 2 hours. Calculate the average speed during the whole journey.​

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)