Zen Manufacturing Company is considering replacing a four-year-old machine with a new, advanced model. The old machine was purchased for $60,000, has an estimated useful life of 10 years with no salvage value, and has annual maintenance costs of $15,000. The new machine would cost $45,000, but annual maintenance costs would be only $6,000. The new machine would have an estimated useful life of 10 years with no salvage value. Using straight-line depreciation and an assumed 40% tax rate, compute the additional annual cash inflow if the old machine is replaced.