AQA D2 2011 January — Question 5

Exam BoardAQA
ModuleD2 (Decision Mathematics 2)
Year2011
SessionJanuary
TopicFixed Point Iteration

5 Each path from \(S\) to \(T\) in the network below represents a possible way of using the internet to buy a ticket for a particular event. The number on each edge represents a charge, in pounds, with a negative value representing a discount. For example, the path SAEIT represents a ticket costing \(23 + 5 - 4 - 7 = 17\) pounds.
\includegraphics[max width=\textwidth, alt={}, center]{172c5c92-4254-4593-b741-1caa83a1e833-12_1023_1330_540_350}
  1. By working backwards from \(\boldsymbol { T }\) and completing the table on Figure 4, use dynamic programming to find the minimum weight of all paths from \(S\) to \(T\).
  2. State the minimum cost of a ticket for the event and the paths corresponding to this minimum cost.
    (3 marks)
  3. \begin{table}[h]
    \captionsetup{labelformat=empty} \caption{Figure 4}
    StageStateFromValue
    1I\(T\)-7
    \(J\)\(T\)-6
    \(K\)\(T\)-5
    2\(E\)\(I\)\(- 7 - 4 = - 11\)
    FI
    \(J\)
    GI
    \(J\)
    \(K\)
    \(H\)\(K\)
    3
    \end{table}