Please show work for #7 if correct will rate and also need #8

Fird Company manufactures a part for its production cycle. The costs per unit for 10,000 units of this part are as follows: 7. Direct materials Direct labor Variable factory overhead Fixed factory overhead Total costs $20 15 16 S66 The fixed factory overhead costs are unavoidable. Assuming no other use of their facilities, the highest price that Fird Company should be willing to pay for the part is a, $41 b. $35 c. $45 d. $51 8. Jack Bowers has paid off the mortgage on his house and continues to live in the house. The interest income forgone by not selling the house and investing the proceeds is an example of a(n) . a sunk cost b. detrimental cost c. opportunity cost . outlay cost