An arc welding machine that is used for a certain joining process costs $$90,000.$ The machine has a life

of $5$ years and salvage value of $$10,000.$ Maintenance, taxes, insurance, and other fixed costs amount to

$$5,000$ per year. The cost of power and supplies is $$28\mathrm{.}00$ per hour of operation and the total operator

cost $($direct and indirect$)$ is $$65\mathrm{.}00$ per hour. If the cycle time per unit of product is $60$ minutes and the

interest rate is $8\%,$ calculate the cost per unit if $($a$)200,($b$)600,$ and $($c$)1,800$ units of output are needed

per year