Edexcel D2 2005 June — Question 9

Exam BoardEdexcel
ModuleD2 (Decision Mathematics 2)
Year2005
SessionJune
TopicNetwork Flows

9.
\includegraphics[max width=\textwidth, alt={}, center]{be329a47-a709-4719-abe6-41d388a6c631-6_540_1291_203_411} This diagram shows a capacitated directed network. The number on each arc is its capacity.
  1. State the maximum flow along
    1. SADT,
    2. SCET,
    3. \(S B F T\).
  2. Show these maximum flows on Diagram 1 below. \section*{Diagram 1}
    \includegraphics[max width=\textwidth, alt={}]{be329a47-a709-4719-abe6-41d388a6c631-6_561_1187_1283_721}
    Take your answer to part (b) as the initial flow pattern.
    1. Use the labelling procedure to find a maximum flow from \(S\) to \(T\). Your working should be shown on Diagram 2 below. List each flow-augmenting route you use, together with its flow. \section*{Diagram 2} \includegraphics[max width=\textwidth, alt={}, center]{be329a47-a709-4719-abe6-41d388a6c631-7_718_1525_205_269}
    2. Draw your final flow pattern on Diagram 3 below.
      \includegraphics[max width=\textwidth, alt={}, center]{be329a47-a709-4719-abe6-41d388a6c631-7_611_1196_1082_717}
    3. Prove that your flow is maximal.
  3. Give an example of a practical situation that could have been modelled by the original network.