Function:If$,$ SUM; Formula: Multiply; Cell Referencing BE$5\mathrm{.}5-$ Using Excel to Evaluate a Make$-$Versus$-$Buy Decision PROBLEM Grunar Industries produces the component parts needed for its popular non$-$commercial$-$use drones. One of the key parts has become more costly to produce than first planned, however, so management is considering outsourcing that part. If the company decides not to manufacture this part, a portion of its fixed manufacturing overhead costs would continue. The costs to produce one such part internally and to purchase on part from the suppler are given here. $2$ Costs to produce internally