Find parameter values from route length

Given the length of an optimal route and other constraints, work backwards to find unknown edge weights or parameters.

2 questions · Standard +0.8

7.04c Travelling salesman upper bound: nearest neighbour method
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Edexcel FD1 2020 June Q6
11 marks Challenging +1.8
6. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{bd357978-6464-43fd-854f-4188b5408e91-08_638_1107_212_479} \captionsetup{labelformat=empty} \caption{Figure 4}
\end{figure} [The total weight of the network is \(320 + x + y\) ]
  1. State, with justification, whether the graph in Figure 4 is Eulerian, semi-Eulerian or neither. The weights on the arcs in Figure 4 represent distances. The weight on arc EF is \(x\) where \(12 < x < 26\) and the weight on arc DG is \(y\) where \(0 < y < 10\) An inspection route of minimum length that traverses each arc at least once is found.
    The inspection route starts and finishes at A and has a length of 409
    It is also given that the length of the shortest route from F to G via A is 140
  2. Using appropriate algorithms, find the value of \(x\) and the value of \(y\).
Edexcel D1 2003 June Q2
6 marks Moderate -0.3
  1. Explain why it is impossible to draw a network with exactly three odd vertices. [2]
\includegraphics{figure_1} The Route Inspection problem is solved for the network in Fig. 1 and the length of the route is found to be 100.
  1. Determine the value of \(x\), showing your working clearly. [4]