network of irrigation ditches is shown in Figure 2.20, with flows measured in thousands...

network of irrigation ditches is shown in Figure 2.20, with flows measured in thousands of liters per day.

(a) Set up and solve a system of linear equations to find the possible flows f₁, . . . , f₅.

(b) Suppose DC is closed. What range of flow will need to be maintained through DB?

(c) From Figure 2.20 it is clear that DB cannot be closed. (Why not?) How does your solution in part (a) show this?

(d) From your solution in part (a), determine the minimum and maximum flows through DB.