Dr. Beth McKenzie, the head administrator at Washington County Regional Hospital, must determine a schedule for nurses to make sure there are enough nurses on duty throughout the day. During the day, the demand for nurses varies. Beth 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 90 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 40 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. McKenzie wants to determine a nursing schedule that will meet the hospital’s minimum requirements throughout the day while using the minimum number of nurses. Formulate and solve a linear programming model for this problem.