A business is operating at 90% of capacity and is currently purchasing a part used in its

manufacturing operations for $15 per unit. The unit cost for the business to make the part is

$20, including fixed costs, and $12, not including fixed costs. All fixed costs are common and

would not change with either option. If 30,000 units of the part are normally purchased

during the year but could be manufactured using unused capacity, what would be the amount

of incremental cost increase or decrease from making the part rather than purchasing it?