Linear programming

2. Between 8 a.m. and noon on Monday, a telephone company has a demand for 500 calls from Boston to Phoenix and for 400 calls from Washington, DC, to Phoenix. The calls can be routed through either Indianapolis or Memphis and then through either Denver or Houston. The capacities between these cities are shown in Table 5.4. Find the maximum number of telephone calls that can be routed from Boston to Phoenix and from Washington to Phoenix using this capacity. Remark In this situation we consider only calls that originate in Boston and Washington and terminate in Phoenix, not calls that originate or terminate in any other cities. Table 5.4 Boston to Indianapolis Washington to Indianapolis Indianapolis to Denver Memphis to Denver Denver to Phoenix 300 250 180 160 500 Boston to Memphis Washington to Memphis Indianapolis to Houston Memphis to Houston Houston to Phoenix 200 250 220 260 400