A plant is operating 24 hours a day. Workers work in one of 3 possible 16-hour shifts as follows: Shift #1: 3 A.M.-7 P.M. Shift #2: 11 A.M.-3 A.M. Shift #3: 7 P.M.-11 A.M. The following table shows the minimum number of workers needed during the 3 periods into which the day is divided: Period Time Number of workers required 1 3 A.M.- 11 A.M. 12 2 11 A.M.- 7 P.M. 10 7 P.M.- 3 A.M. The question is to determine how many workers should report for work in each shift, so that the total number of workers required for one day's operations is minimized. Please note that each shift of workers covers 2 periods in a day. Let x1, x2 and 3 be the number of workers working in shifts 1, 2 and 3 respectively. [1] Please write down the objective function of this problem including whether to minimize or maximize [2] Please write down all constraints for this problem [3] What is the minimum total number of workers required for a day's operation