6. Chapter 6, Problem 11. Radford Castings can produce brake shoes on six different machines. The following table summarizes the manufacturing costs associated with producing the brake shoes on each machine along with the available capacity on each machine. If the company has received an order for 1,800 brake shoes, how should it schedule these machines? Machine Fixed Cost Variable Cost Capacity $1000 $21 500 $ 950 $23 600 $ 875 $25 750 QUIAONE $ 850 $24 400 $ 800 $20 600 $ 700 $26 800 a. Formulate an ILP model for this problem. b. Create a spreadsheet model for this problem and solve it. .. What is the optimal solution