6.122 WP SS An electrically driven pump operating at steady state draws water from a pond at a pressure of 1 bar and a rate of 50 kg/s and delivers the water at a pressure of 4 bar. There is no sig- nificant heat transfer with the surroundings, and changes in kinetic and potential energy can be neglected. The isentropic pump effi- ciency is 75%. Evaluating electricity at 8.5 cents per kW -h, estimate the hourly cost of running the pump.