Edexcel D1 — Question 5

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
TopicPermutations & Arrangements
TypeAssignment/allocation matching problems

5. This question should be answered on the sheet provided. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{e1fd42f7-c97c-4bf2-92d3-69afc8bb6e29-05_956_1561_312_242} \captionsetup{labelformat=empty} \caption{Fig. 2}
\end{figure} Figure 2 shows a weighted network representing the paths in a certain part of St. Andrews. The numbers on the arcs represent the lengths of the paths in metres.
  1. Use Dijkstra's algorithm to find a route of minimum length from \(P\) to \(F\). You do not need to consider routes via vertex \(Q\). You must show clearly:
    1. the order in which you labelled the vertices,
    2. how you found a route of minimum length from your labelling. Each night a security guard walks along each of the paths in Figure 2 at least once.
  2. The security office is at vertex \(A\), so she must start and finish her inspection at \(A\). Find the minimum distance that she must walk each night.
    (4 marks)