The graph in figure $5\mathrm{.}38$ represents various flows that can occur through a sewage treatment plant with the numbers on the arcs representing the maximum flow $($in tons of sewage per hour$)$ that can be accommodated. Formulate an LP model to determine the maximum per hour$)$ that can be accommodated. Formulate an LP model to determine the maximum tons of sewage per hour that can be processed by this plant.