How to find optimal value , along with the two dimensional coordinates of it using PSO

There are 10 factories located at different places. each of these factories produces 4 different items , cost of each item is w, x, y, z.

constraints w+x+y+z =1000;

x * y= 10;

(a) find factory wihich gives best value, along with its coordinates and distance form each other and the customer