Construct a network diagram to represent practical situations, e.g. tra cks connecting camp sites in a national park, a social network, a transport network with one -way streets, the results of a round-robin sporting competition.

A delivery company operates in a business district with five locations: Head Office (H), Warehouse (W), Retail Store (R), Distribution Centre (D), and Service Point (S). The table below shows the direct delivery routes between locations and whether each route is one-way or two-way. (a) Construct a network diagram to represent all the direct delivery routes, using arrows to indicate the direction of one-way routes and lines without arrows for two-way routes. Label all vertices. (3 marks) (b) Determine the total number of edges in the network. (1 mark)