Please show all work and in excel if possible. Thank you!

6. Amazon sells 10,000 Lenovo PCs every month. Each PC costs $500 and Amazon has an annual holding cost of 20 percent. For what fixed cost per order would an order size of 10,000 units be optimal? For what fixed cost per order would an order size of 2,500 units be optimal? 7. A steel rolling mill can produce I-beams at the rate of 20 tons per week. Customer demand for the beams is 5 tons per week. To produce I-beams, the mill must go through a setup that requires changing to the appropriate rolling patterns. Each setup costs the mill $10,000 in labor and lost production. I-beams cost the mill \$2,000 per ton and the mill has an annual holding cost of 25 percent. What is the optimal production batch size for I-beams? What is the annual setup cost of the optimal policy? What is the annual holding cost