A 5000-hp variable-frequency motor drive is under consideration using either an induction motor or a synchronous motor. The estimated system efficiency of the synchronous motor with drive is 92%, and that of the induction motor with drive is 88%. The motor is projected to run 600 h per month on average. Determine the total energy cost savings over a 30-year expected life of the system using the synchronous motor drive if the energy cost is 12 cents/kWh. Also determine the present worth of lifetime savings discounted at 0.75% per month.