$6-$ A job can be done with Machine A that costs $57$$$12,500$ and has annual end$-$of$-$year maintenance costs of $$5000$; its salvage value after $3$ years is $$2000.$ Or the job can be done with Machine B$,$ which costs $$15,000$ and has end$-$of$-$year maintenance costs of $$4000$ and a salvage value of $$1500$ at the end of $4$ years. These investments can be repeated in the future, and your work is expected to continue indefinitely. Use present worth, annual worth, and capitalized cost to compare the machines. The interest rate is $5\frac{\%}{?}$ year. Contributed by D$.$ P$.$ Loucks, Cornell University