Edexcel D2 2010 June — Question 5

Exam BoardEdexcel
ModuleD2 (Decision Mathematics 2)
Year2010
SessionJune
TopicNetwork Flows

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{a91f96a3-a9b4-4bf5-bfdf-93c34912e54a-6_1012_1696_233_182} \captionsetup{labelformat=empty} \caption{Figure 2}
\end{figure} Figure 2 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. State the value of the initial flow.
    (1)
  2. State the capacities of cuts \(\mathrm { C } _ { 1 }\) and \(\mathrm { C } _ { 2 }\).
    (2)
  3. By entering values along DH, FH, FI and IT, complete the labelling procedure on Diagram 1 in the answer book.
    (2)
  4. Using Diagram 1, increase the flow by a further 4 units. You must list each flow-augmenting route you use, together with its flow.
    (3)
  5. Prove that the flow is now maximal.
    (2)