Suppose that you are asked to locate police stations in Little Rock. There are five possible locations (A, B, C, D, E) for stations and six districts (1,2,3,4,5,6) to serve. A station in a given location can only serve districts in its vicinity. A station can serve several districts, but every district must be served by at least one station. The table below shows which station can serve which districts:
Possible locations A B C D E
Districts served 1,3,5 2,5 3,4 1,3,4 2,6
a) Provide a formulation to minimize the number of police stations required to serve Little Rock districts.