42. TRAFFIC CONTROL The accompanying figure shows the flow of traffic near a city's Civic Center during the rush hours on a typical weekday. Each road can handle a maximum of 1000 cars/hour without causing congestion. The flow of traffic is controlled by traffic lights at each of the five Intersections. a. Set up a system of linear equations describing the traffic flow. b. Solve the system devised in part a. and suggest two possible traffic-flow patterns that will ensure no traffic congestion. c. Suppose 7th Avenue between 3rd and 4th Streets is soon to be closed for road repairs. Find one possible traffic-flow pattern that will result in a smooth flow of traffic