Edexcel D1 2018 June — Question 2

Exam BoardEdexcel
ModuleD1 (Decision Mathematics 1)
Year2018
SessionJune
TopicCombinations & Selection

2. (a) Define the terms
  1. alternating path,
  2. complete matching.
    (4) \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{5b18e92c-540e-4e89-8d60-d60294f50dda-03_521_614_450_351} \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{figure} \begin{figure}[h]
    \includegraphics[alt={},max width=\textwidth]{5b18e92c-540e-4e89-8d60-d60294f50dda-03_509_604_456_1098} \captionsetup{labelformat=empty} \caption{Figure 2}
    \end{figure} Figure 1 shows the possible allocations of six workers, \(\mathrm { A } , \mathrm { B } , \mathrm { C } , \mathrm { D } , \mathrm { E }\) and F , to six tasks, \(1,2,3,4,5\) and 6. Each task must be assigned to only one worker and each worker must be assigned to exactly one task. Figure 2 shows an initial matching.
    (b) Starting from the given initial matching, use the maximum matching algorithm to find an alternating path from F to 1. Hence find an improved matching. You must write down the alternating path used and state your improved matching.
    (3)
    (c) Explain why it is not possible to find a complete matching.
    (1) Worker C has task 1 added to his possible allocations.
    (d) Starting from the improved matching found in (b), use the maximum matching algorithm to find a complete matching. You must write down the alternating path used and state your complete matching.