Let x1, x2, and x3 represent the number of cars per hour that are traveling on AC, AB, and BC, respectively. Consider intersection A. There are 300 + 200 = 500 cars per hour entering A and x1 + x2 cars leaving A. Therefore, x1 + x2 = 500. For intersection B, we have 50 + x2 cars per hour entering the intersection and 100 + x3 cars leaving the intersection. Thus 50 + x2 = 100 + x3, or x2 – x3 = 50. Applying the same reasoning to C, we have x1 + x3 = 450. These equations result in the system of equations:

Using this example, estimate the traffic flow for a roundabout presented below. The graphical model shows the number of cars per hour that are entering or leaving a roundabout. If the portion of the roundabout between A and B has an estimated traffic flow of from 6[e] to 8[a]cars per hour, what is the estimated traffic flow between C and A, and between B and C?

6[2] 8[3]