Answer:
The company should make the components because incremental costs are $2 less than the purchase price
Step-by-step explanation:
The cost of making each unit of component = Direct Labour + Direct Material + Variable Overhead*
*The overhead cost of $4 contains both a fixed and variable element. It has been mentioned that 25% of overhead cost is incremental i.e. it increases with each additional unit produced (marginal cost). The incremental cost is the variable element.
Variable element = $4 x 25% = $1
Fixed element = $4 x 75% = $3
Thus, the cost of making each unit of component = $5 + $2 + $1 = $8,
whereas the cost of purchasing each unit of complement is $10. Hence, the company should produce the component as it is less by $2 ($10 - $8) to produce than it is to purchase.