Trauma center
A trauma center keeps ambulances at locations throughout the east side of a city in an attempt to minimize the response time in the event of an emergency. The times, in minutes, from the ambulance locations to the population centers are given in the table at the top of the next column.
POPULATION
AMBULANCE
LOCATIONS EAST NORTH-EAST SOUTH-EAST CENTRAL
SITE 1 12 8 9 13
SITE 2 10 9 11 10
SITE 3 11 12 14 11
SITE 4 13 11 12 9
Find the optimal assignment of ambulances to population centers that will minimize the total emergency response time.