An industrial park consists of 16 buildings. The corporations in the park are sharing the cost of construction and maintenance for a new first-aid center. Because of the park’s layout, distances between buildings are most closely approximated by a rectilinear distance measure. Weights for the buildings are determined based on the frequency of accidents. Find the optimal location of the first-aid center to minimize the weighted sum of the rectilinear distances to the 16 buildings.

Building ai bi wi Building ai bi wi 1 0 0 9 9 14 6 11 2 10 3 7 10 19 0 17 3 8 8 4 11 20 4 14 4 12 20 3 12 14 25 6 5 4 9 2 13 3 14 5 6 18 16 12 14 6 6 8 7 4 1 4 15 9 21 15 8 5 3 5 16 10 10 4