Formulate the employee schedule using the below LP decision variables.

Let, X1 = Number of delivery staff with Monday and Tuesday off
X2 = Number of delivery staff with Tuesday and Wednesday off
X3 = Number of delivery staff with Wednesday and Thursday off
X4 = Number of delivery staff with Thursday and Friday off
X5 = Number of delivery staff with Friday and Saturday off
X6 = Number of delivery staff with Saturday and Sunday off
X7 = Number of delivery staff with Sunday and Monday off
Minimize S = X1 + X2 + X3 + X4 + X5 + X6 + X7
Subject to:
Monday requirement: X2 + X3 + X4 + X5 + X6 ≥ 16
Tuesday requirement: X3 + X4 + X5 + X6 + X7 ≥ 21
Wednesday requirement: X1 + X4 + X5 + X6 + X7 ≥ 20
Thursday requirement: X1 + X2 + X5 + X6 + X7 ≥ 25
Friday requirement: X1 + X2 + X3 + X6 + X7 ≥ 20
Saturday requirement: X1 + X2 + X3 + X4 + X7 ≥ 9
Sunday requirement: X1 + X2 + X3 + X4 + X5 ≥ 10
Non-negativity: All variables ≥ 0