Answer:
Contribution margin per machine hour for bread machines = $320
Explanation:
From the question, the following can be deduced:
Selling price Variable costs Contribution/unit
Toaster Ovens $100 $60 $40
Bread machines $140 $60 $80
In each machine hour, six toaster ovens per machine hour and four bread machines are manufactured
Total contribution margin per machine hour = 6*40+4*80 =$560
Of which contribution margin per machine hour for bread machines = 4*80=$320