a proposed cost-saving device has an installed cost of $765,000. the device will be used in a five-year project but is classified as three-year macrs property for tax purposes (macrs schedule). the required initial net working capital investment is $67,000, the tax rate is 21 percent, and the project discount rate is 9 percent. the device has an estimated year 5 salvage value of $103,000. what level of pretax cost savings do we require for this project to be profitable?