Determine which tracts should receive a station to minimize
the total cost of stations while ensuring that each
tract has at least one station close enough to respond to
a fire in no more than 15 minutes (on the average).In contrast to the original problem, note that the total number of
fire stations is no longer fixed. Furthermore, if a tract without a
station has more than one station within 15 minutes, it is no longer
necessary to assign this tract to just one of these stations.
(a) Formulate a complete pure BIP model with 5 binary variables
for this problem