Please answer using branch & bound method.

Question 2 (Problem 9-34, page 357-358 of text) Jarvis and Associates (1978). Seven cities are being considered as potential locations for the construction of at most four wastewater treatment plants. The following table provides the data for the situation. Missing links indicate that a pipeline cannot be constructed. Cost ($) of pipeline construction between citites per 1000 gal/hr capacity 1 2 3 4 5 6 7 From 1 100 200 120 50 150 2 3 400 90 120 120 4 120 5 200 100 200 70 6 110 200 1.00 180 150 1.60 1.20 2.00 1.80 0.90 1.40 7 Cost (S million) of plant construction Population (1000s) 50 100 45 90 75 60 30 The capacity of a pipeline (in gallons per hour) is a direct function of the amount of wastewater generated, which is a function of the populations. Approximately 500 gallons per 1000 residents are discharged in the sewer system per hour. The maximum plant capacity is 100,000 gal/hr. Determine the optimal location and capacity of the plants