The Southfork Feed Company makes a feed mix from four ingredientsoats, corn, soybeans, and a vitamin supplement. The company has 300 pounds of oats, 400 pounds of corn, 200 pounds of soybeans, and 100 pounds of vitamin supplement available for the mix. The company has the following requirements for the mix: - At least 30% of the mix must be soybeans. - At least 20% of the mix must be the vitamin supplement. - The ratio of corn to oats cannot exceed 2 to 1 . - The amount of oats cannot exceed the amount of soybeans. - The mix must be at least 500 pounds. A pound of oats costs $0.50, a pound of corn, $1.20, a pound of soybeans, $0.60, and a pound of vitamin supplement, $2.00. The feed company wants to know the number of pounds of each ingredient to put in the mix to minimize cost. a. Formulate a linear programming model for this problem. b. Solve the model by using the computer. 4. Dr. Maureen Becker, the head administrator at Jefferson County Regional Hospital, must determine a schedule for nurses to make sure there are enough of them on duty throughout the day. During the day, the demand for nurses varies. Maureen has broken the day into twelve 2-hour periods. The slowest time of the day encompasses the three periods from 12:00 A.M. to 6:00 A.M., which, beginning at midnight, require a minimum of 30, 20, and 40 nurses, respectively. The demand for nurses steadily increases during the next four daytime periods. Beginning with the 6:00 A.M.-8:00 A.M. period, a minimum of 50,60,80, and 80 nurses are required for these four periods, respectively. After 2:00 P.M. the demand for nurses decreases during the afternoon and evening hours. For the five 2-hour periods beginning at 2:00 P.M. and ending at midnight, 70, 70, 60, 50, and 50 nurses are required, respectively. A nurse reports for duty at the beginning of one of the 2-hour periods and works 8 consecutive hours (which is required in the nurses' contract). Dr. Becker wants to determine a nursing schedule that will meet the hospital's minimum requirements throughout the day while using the minimum number of nurses. a. Formulate a linear programming model for this problem. b. Solve this model by using the computer