May I ask how to solve the quantity here, the one in green highlight? I don't know how to solve without using excel. please explain to me thank you

Cutting Cafeteria Costs A cafeteria at All-State University has one special dish it serves like clockwork every Thursday at noon. This supposedly tasty dish is a casserole that contains sauted onions, boiled sliced potatoes, green beans, and cream of mushroom soup. Unfortunately, students fail to see the special quality of this dish, and they loathingly refer to it as the Killer Casserole. The students reluctantly eat the casserole, however, because the cafeteria provides only a limited selection of dishes for Thursday's lunch (namely, the casserole). Maria Gonzalez, the cafeteria manager, is looking to cut costs for the coming year, and she believes that one sure way to cut costs is to buy less expensive and perhaps lower quality ingredients. Because the casserole is a weekly staple of the cafeteria menu, she concludes that if she can cut costs on the ingredients purchased for the casserole, she can significantly reduce overall cafeteria operating costs. She therefore decides to invest time in determining how to minimize the costs of the casserole while maintaining nutritional and taste requirements. Maria focuses on reducing the costs of the two main ingredients in the casserole, the potatoes and green beans. These two ingredients are responsible for the greatest costs, nutritional content, and taste of the dish. Maria buys the potatoes and green beans from a wholesaler each week. Potatoes cost $0.40 per pound (lb), and green beans cost $1.00 per lb. All-State University has established nutritional requirements that each main dish of the cafeteria must meet. Specifically, the dish must contain 180 grams (g) of protein, 80 milligrams (mg) of iron, and 1,050 mg of vitamin C. (There are 454 g in one lb and 1,000 mg in one g.) For simplicity when planning, Maria assumes that only the potatoes and green beans contribute to the nutritional content of the casserole. Because Maria works at a cutting-edge technological university, she has been searching for information on the Internet to find the nutritional content of potatoes and green beans. Her research yields the following nutritional information about the two ingredients. Potatoes Green Beans Protein 1.5 g per 100 g 5.67 g per 10 ounces Iron 0.3 mg per 100 g 3.402 mg per 10 ounces Vitamin C 12 mg per 100 g 28.35 mg per 10 ounces (There are 28.35 g in one ounce.) Page 62 Edson Branner, the cafeteria cook who is surprisingly concerned about taste, informs Maria that an edible casserole must contain at least a six-to-five ratio in the weight of potatoes to green beans. Given the number of students who eat in the cafeteria, Maria knows that she must purchase enough potatoes and green beans to prepare a minimum of 10 kilograms (kg) of casserole each week. (There are 1,000 g in one kg.) Again, for simplicity in planning, she assumes that only the potatoes and green beans determine the amount of casserole that can be prepared. Maria does not establish an upper limit on the amount of casserole to prepare since she knows all leftovers can be served for many days thereafter or can be used creatively in preparing other dishes. a. Determine the amount of potatoes and green beans Maria should purchase each week for the casserole to minimize the ingredient costs while meeting nutritional, taste, and demand requirements. Figure 2: Solver calculation F 4 > A B D E 1 Potatoes Green beans 2 Unit cost(per lb.) $0.40 $1.00 3 CONSTRAINTS Total nutrition 5 Protein(g) 6.804 9.072 194.87 6 Iron(mg) 1.361 5.443 80 7 Vitamin C(mg) 54.432 45.36 1251.27 8 9 Potatoes Green beans Total weight 10 Quantity(lb) 13.57 11.31 24.87 11 12 Taste 67.83 67.83 13 TOTAL COST 16.73 Nutritional requirement 180 80 1,050 22.046 14 Figure 3: Result of quantities for cost minimization Thus, person M should purchase 13.57b. of potatoes and 11.31b. of green beans for getting a minimum cost of $16.73