Final answer:
Harmony's maximum willingness to pay the external vendor for the 100 parts is $100,000.
Step-by-step explanation:
Harmony's maximum willingness to pay the external vendor for the 100 parts can be calculated by considering the costs incurred by producing the parts internally and the fixed costs that would be eliminated if purchased from the vendor.
The total costs for producing the parts internally are $60,000 for direct materials, $12,500 for direct labor, $22,500 for variable overhead, and $15,000 for fixed overhead, which equals $110,000.
If Harmony purchases the components from the external vendor, $10,000 of fixed costs would be eliminated, resulting in $100,000 in total costs.
The maximum amount Harmony would be willing to pay the external vendor can be calculated by subtracting the eliminated fixed costs from the total costs of producing the parts internally, which is $110,000 - $10,000 = $100,000.