AQA D1 2016 June — Question 3

Exam BoardAQA
ModuleD1 (Decision Mathematics 1)
Year2016
SessionJune
TopicMinimum Spanning Trees

3 The network below shows vertices \(A , B , C , D\) and \(E\). The number on each edge shows the distance between vertices.
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    1. In the case where \(x = 8\), use Kruskal's algorithm to find a minimum spanning tree for the network. Write down the order in which you add edges to your minimum spanning tree.
    2. Draw your minimum spanning tree.
    3. Write down the length of your minimum spanning tree.
  1. Alice draws the same network but changes the value of \(x\). She correctly uses Kruskal's algorithm and edge \(C D\) is included in her minimum spanning tree.
    1. Explain why \(x\) cannot be equal to 7 .
    2. Write down an inequality for \(x\).