Combined-cycle power plants use two combustion tur bines to produce electricity. Heat from the first turbin e's exhaust is captured to heat water and produce stea m sent to a second steam turbine that generates additi onal electricity. A 968-megawatt combined-cycle gas fir ed plant can be purchased for $450 million, has no salv age value, and produces a net cash flow (revenues less expenses) of $12 billion over its expected 30-year life. If the hurdle rate (MARR) is 12% per year what is the simp le payback period for the plant