Edexcel D1 2008 January — Question 3

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2008
SessionJanuary
TopicRoute Inspection

3. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{7396d930-0143-4876-b019-a4d73e09b172-4_755_1132_239_468} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} Figure 4 models a network of roads in a housing estate. The number on each arc represents the length, in km , of the road. The total weight of the network is 11 km .
A council worker needs to travel along each road once to inspect the road surface. He will start and finish at A and wishes to minimise the length of his route.
  1. Use an appropriate algorithm to find a route for the council worker. You should make your method and working clear. State your route and its length.
    (6) A postal worker needs to walk along each road twice, once on each side of the road. She must start and finish at A . The length of her route is to be minimised. You should ignore the width of the road.
    1. Explain how this differs from the standard route inspection problem.
      (1)
    2. Find the length of the shortest route for the postal worker.
      (2)