Subassemblies for a model IV microscope are purchased $71 apiece. The annual demand is 350 units and is expected to continue for 3 years. With equipment purchased and installed for $21,000, the production costs to internally produce the subassemblies should be $18,500 for the first year and $12,250 in each of the last 2 years. The equipment will have no salvage value. Should the company make or buy assemblies. Use IRR method. MARR= 18%.