Edexcel FD1 AS 2023 June — Question 5

Exam BoardEdexcel
ModuleFD1 AS (Further Decision 1 AS)
Year2023
SessionJune
TopicRoute Inspection

5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{9edb5209-4244-4916-b3ee-d77e395e8cab-06_873_739_178_664} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} [The weight of the network is \(20 x + 3\) ] Figure 4 shows a graph G that contains 8 arcs and 6 vertices.
  1. State the minimum number of arcs that would need to be added to make G into an Eulerian graph.
  2. Explain whether or not the route \(\mathrm { A } - \mathrm { C } - \mathrm { F } - \mathrm { E } - \mathrm { C } - \mathrm { D } - \mathrm { B }\) is an example of a path on G. Figure 4 represents a network of 8 roads in a city. The expression on each arc gives the time, in minutes, to travel along the corresponding road. You are given that \(x > 1.6\)
    A route is required that
    • starts and finishes at the same vertex
    • traverses each road at least once
    • minimises the total time taken
    The route inspection algorithm is applied to the network in Figure 4 and the time taken for the route is found to be at most 189 minutes. Given that the inspection route contains two roads that need to be traversed twice,
  3. determine the range of possible values of \(x\), making your reasoning clear.