Edexcel D1 2008 June — Question 5

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2008
SessionJune
TopicCombinations & Selection

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{be646775-535e-4105-86b4-ffc7eda4fa51-5_819_1421_251_322} \captionsetup{labelformat=empty} \caption{Figure 5}
\end{figure} Figure 5 shows a capacitated, directed network of pipes. The number on each arc represents the capacity of that pipe. The numbers in circles represent a feasible flow.
  1. State the values of \(x\) and \(y\).
  2. List the saturated arcs.
  3. State the value of the feasible flow.
  4. State the capacities of the cuts \(\mathrm { C } _ { 1 } , \mathrm { C } _ { 2 }\), and \(\mathrm { C } _ { 3 }\).
  5. By inspection, find a flow-augmenting route to increase the flow by one unit. You must state your route.
  6. Prove that the new flow is maximal.