Jack has built a concrete plant, and he's decided to try a heat pump boiler system for his water heating needs to save on energy costs and reduce carbon emissions. His boiler maintains about 10 , 000 gallons of water at around 129 F . The heat pump system gets its input heat from the soil deep underground because the temperature of this soil remains pretty stable even in cold weather. In fact, the soil temperature in his system is always around 58 F . The boiler takes thermal energy out of the soil at a rate of 48 k W . While heating the water in the tank, the water heater uses electrical energy at a rate of about 30 k W . At what percent of its theoretical maximum coefficient of performance is the water heater operating?