Troy Engines, Limited, manufactures a variety of engines for use in heavy equipment. The company has always produced all of the parts for its engines, including the carburetors. An outside supplier offered to sell one type of carburetor to Troy Engines, Limited, for a cost of $$40$ per unit. To evaluate this offer, Troy Engines, Limited, summarized the cost of producing the carburetor internally as follows:

$\backslash$table$[[,$Per,$15,000$ Units$],[,$Unit,Per Year$],[$Direct materials,$15,$$$225,000$