Knives Out Co$.$ is considering when to replace its old machine. The company faces $2$ options: $(1)$ replace the old machine now, or $(2)$ replace it at the end of six years. Currently, the old machine has a salvage value of $$3$ million and book value of $$1\mathrm{.}8$ million. If the machine is not sold, it will require maintenance costs of $$775,000$ at the end of the year over the next six years. The depreciation expense for the machine is $$300,000$ per year. At the end of six years, the machine will have a salvage value of only $$100,000$ and a book value of $$0.$ If the company replaces the old machine now, the new machine will cost $$4\mathrm{.}8$ million and will require maintenance costs of $$320,000$ at the end of each year during its economic life of six years. At the end of six years, the new machine will have a salvage value of $$900,000.$ It will be fully depreciated by the straight$-$line method. If Knives out replace the old machine in six years time, a replacement machine will cost $$3\mathrm{.}4$ million. The company will need to purchase this machine regardless of what choice it makes today. The corporate tax rate is $21\%$ and the appropriate discount rate is $7\mathrm{.}5\%.$ The company is assumed to earn sufficient revenues to generate tax shields from depreciation. Should Knives Out Co$.$ replace the old machine now or at the end of six years? Please do not skip any part and show workings so i can understand