egion to the next are summarized in the following table: The population (in 1,000 s) in regions 1 through 6 are estimated, respectively, as 15,35,20,21,37, and 60 . In which two regions should the ambulances be placed? (a) Formulate an ILP model for this problem to maximize the number of residents (in 1,000 s) that can be reached within an average of at most 4 minutes in emergency situations using 2 ambulances. (Let Xj=1 if an ambulance is placed in region i and 0 otherwise. Let Yj=1 if the placement of the ambulances allows region i to be serviced within 4 minutes and 0 otherwise. In your constraints for setting the value of Yi, only use coefficients of 1 or 1.) (b) Implement your model in a spreadsheet and solve it. What is the optimal solution? (x1,x2,x3,x4,x5,x6)=( (c) What is the smallest number of ambulances required to provide coverage within 4 minutes to all residents? ambulances (d) Suppose the county wants to locate three ambulances in such a way to provide coverage to all residents within 4 minutes and maximize the redundancy in the system. (Assume redundancy means being able to provide service by one or more ambulances within 4 minutes.) Where should the ambulances be located? (Select all that apply. Calculate redundancy as the sum of the total number of people (in 1,000s) each ambulance can serve within 4 minutes.) region 1 region 2 region 3 region 4 region 5 region 6 egion to the next are summarized in the following table: The population (in 1,000 s) in regions 1 through 6 are estimated, respectively, as 15,35,20,21,37, and 60 . In which two regions should the ambulances be placed? (a) Formulate an ILP model for this problem to maximize the number of residents (in 1,000 s) that can be reached within an average of at most 4 minutes in emergency situations using 2 ambulances. (Let Xj=1 if an ambulance is placed in region i and 0 otherwise. Let Yj=1 if the placement of the ambulances allows region i to be serviced within 4 minutes and 0 otherwise. In your constraints for setting the value of Yi, only use coefficients of 1 or 1.) (b) Implement your model in a spreadsheet and solve it. What is the optimal solution? (x1,x2,x3,x4,x5,x6)=( (c) What is the smallest number of ambulances required to provide coverage within 4 minutes to all residents? ambulances (d) Suppose the county wants to locate three ambulances in such a way to provide coverage to all residents within 4 minutes and maximize the redundancy in the system. (Assume redundancy means being able to provide service by one or more ambulances within 4 minutes.) Where should the ambulances be located? (Select all that apply. Calculate redundancy as the sum of the total number of people (in 1,000s) each ambulance can serve within 4 minutes.) region 1 region 2 region 3 region 4 region 5 region 6
