A city wants to locate 2 new fire fighting ladder trucks to maximize the number of tall buildings which they can cover within a 3 minute response time. The city is divided into 4 zones. The fire chief wants to locate no more than one of the trucks in either Zone 1 or Zone 2. The number of tall buildings in each zone and the travel time between zones is listed below.

		to zones
No tall buildings	from zones	1	2	3	4
50	1	0	2	1	6
90	2	2	0	4	5
60	3	1	4	0	1
70	4	6	5	1	0

a. Write the Mathematical ILP formulation for this problem.

b. Solve the problem using Solver for the optimal value objective function and the locations the fire trucks.