Since the Cost of Buy is lower than the Cost of Make, the company should buy the units at a net benefit of $600.
The decision can be taken by determining the benefit or loss as follows:
1) Calculation of Cost of Make
Cost of Make = Total variable production costs of making the units + Avoidable Fixed Cost of Make = $11,100 + $1,500 = $12,600
2) Calculation of Cost of Buy
Cost of Buy = Buy price per unit * Number of units = $4 * 3,000 = $12,000
3) Since the Cost of Buy is lower than the Cost of Make, it means there is a benefit of $600 calculated as follows:
Benefit from Buy = Cost of Make - Cost of Buy = $12,600 - $12,000 = $600.
Learn more about make or buy decisions at: https://brainly.com/question/13132020.