Edexcel D1 2007 June — Question 8

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2007
SessionJune
TopicNetwork Flows

8. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{0fdc5a3c-97e7-46e3-a57c-45a13755f0e5-9_1131_1653_242_207} \captionsetup{labelformat=empty} \caption{Figure 6}
\end{figure} Figure 6 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) Diagram 3 in the answer book shows the labelling procedure applied to the above network.
  3. Using Diagram 3, increase the flow by a further 19 units. You must list each flow-augmenting path you use, together with its flow.
    (5)
  4. Prove that the flow is now maximal.