Edexcel D2 2014 June — Question 5

Exam BoardEdexcel
ModuleD2 (Decision Mathematics 2)
Year2014
SessionJune
TopicNetwork Flows

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{d708ce08-4ea3-4a13-a39c-00efcde32c57-5_707_969_237_523} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} Figure 1 shows a capacitated, directed network. The number on each arc represents the capacity of that arc. The numbers in circles represent an initial flow.
    1. Add a supersource, S , and a supersink, T , and corresponding arcs to Diagrams 1 and 2, in the answer book.
    2. Enter the flow value and appropriate capacity on each of the arcs you have added to Diagram 1.
  1. Complete the initialisation of the labelling procedure on Diagram 2 by entering values along the new arcs from \(S\) and \(T\), and along \(A B , A D\) and \(D _ { 2 }\).
  2. Hence use the labelling procedure to find a maximum flow through the network. You must list each flow-augmenting route you use, together with its flow.
  3. Draw a maximal flow pattern on Diagram 3 in the answer book.
  4. Prove that your flow is maximal.