Question number 4 in the second image is based on the problem in the first image. The third image is the solution of the problem. I did not understand the two constraints highlighted in the solution image. I would like an explanation for these two constraints.

different days of the on in Table 4. Union ays and then receive A post office requires different numbers of full-time employees on differen week. The number of full-time employees required on each day is given in Tal rules state that each full-time employee must work five consecutive days and two days off. For example, an employee who works Monday to Friday must be off urday and Sunday. The post office wants to meet its daily requirements using on time employees. Formulate an LP that the post office can use to minimize the nu full-time employees who must be hired. to Friday must be off on Sat. nents using only full- minimize the number of Number of Full-time Employees Required Day 17 1 = Monday 2 = Tuesday 3 = Wednesday 4 = Thursday 5 = Friday 6 = Saturday 7 = Sunday 4 Suppose the post office had 25 full-time employees and was not allowed to hire or fire any employees. Formulate an LP that could be used to schedule the employees in order to maximize the number of weekend days off received by the employees. Set: T: the set of employees {1, 2..., 25} J: the set of days of the week {1,2,3,4,5,6,7} 1;: the set of days which if an employee starts working, can cover day j (for example for j=7 the set is {3,4,5,6,7}) Parameters: dj: Number of full time employees needed in dayj Variable: ns1 if employee i start at day j otherwise v. {1 if employee i is off in dayj otherwise Xij 1 0 Yij l o Sit: Max Lier Eje{6,73 Vij Eier EkelXik 2 dj Vij S1-Ekey Ljej Xij = 1 Xij E (0,1) Vij E (0,1) Vje) Vi elj {6,7} Vielje) viel,j EJ