electrically driven pump operating at steady state draws water from a pound at a pressure of 1 bar and a a rate of 50 kg/s and delivers the water at a pressure of 4 bar. there is no significant heat transfer with surroundings and changes in kinetic and potential energy can be neglected. the isentropic pump efficiency is 75%. evaluating electricity at 8.5 cents per kW.h, estimate the hourly cost of running the pump.