LP Formulation

minimize 1.2 XDR + 1.4 XDM + 1.4 XDN + 0.3 XDS +

0.2 XSPS + 0.15 XSA +

0.25 XPSR + 0.2 XPSM + 0.15 XPSN +

0.25 XAR + 0.2 XAM + 0.15 XAN

subject to

XDR + XDM + XDN + XDS = 20000000 ! D

XSPS + XSA - XDS = 0 ! S

XPSR + XPSM + XPSN - XSPS = 0 ! PS

XAR + XAM + XAN - XSA = 0 ! PA

-XPSR - XAR - XDR = - 4000000 ! R

-XPSM - XAM - XDM = - 12000000 ! M

-XPSN - XAN - XDN = - 4000000 ! N

XSPS <= 14000000 ! At most 70% through canal

XSA <= 10000000 ! Pipeline capacity

end