| Exam Board | AQA |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2005 |
| Session | June |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Matchings and Allocation |
| Type | Maximum matching algorithm application |
| Difficulty | Moderate -0.8 This is a standard textbook application of the maximum matching algorithm using alternating paths on a small bipartite graph. The question provides an initial matching and explicitly tells students to use alternating paths, making it more routine than problem-solving. Drawing the bipartite graph is straightforward, and finding alternating paths with only 5 nodes requires minimal insight. This is easier than average A-level content. |
| Spec | 7.02e Bipartite graphs: K_{m,n} notation7.02r Graph modelling: model and solve problems using graphs |
| Preferences | |
| Grainne ( \(G\) ) | Audi \(( A )\) or Peugeot ( \(P\) ) |
| Kath ( \(K\) ) | Peugeot ( \(P\) ) or Ford Focus ( \(F\) ) |
| Mary ( \(M\) ) | Jaguar ( \(J\) ) or Range Rover ( \(R\) ) |
| Nicola ( \(N\) ) | Audi \(( A )\) or Ford Focus ( \(F\) ) |
| Stella ( \(S\) ) | Jaguar ( \(J\) ) or Audi ( \(A\) ) |
2 A father is going to give each of his five daughters: Grainne ( $G$ ), Kath ( $K$ ), Mary ( $M$ ), Nicola ( $N$ ) and Stella ( $S$ ), one of the five new cars that he has bought: an Audi ( $A$ ), a Ford Focus ( $F$ ), a Jaguar ( $J$ ), a Peugeot ( $P$ ) and a Range Rover ( $R$ ).
The daughters express preferences for the car that they would like to be given, as shown in the table.
\begin{center}
\begin{tabular}{|l|l|}
\hline
& Preferences \\
\hline
Grainne ( $G$ ) & Audi $( A )$ or Peugeot ( $P$ ) \\
\hline
Kath ( $K$ ) & Peugeot ( $P$ ) or Ford Focus ( $F$ ) \\
\hline
Mary ( $M$ ) & Jaguar ( $J$ ) or Range Rover ( $R$ ) \\
\hline
Nicola ( $N$ ) & Audi $( A )$ or Ford Focus ( $F$ ) \\
\hline
Stella ( $S$ ) & Jaguar ( $J$ ) or Audi ( $A$ ) \\
\hline
\end{tabular}
\end{center}
\begin{enumerate}[label=(\alph*)]
\item Show all these preferences on a bipartite graph.
\item Initially the father allocates the Peugeot to Kath, the Jaguar to Mary, and the Audi to Nicola.
Demonstrate, by using alternating paths from this initial matching, how each daughter can be matched to a car which is one of her preferences.\\
(6 marks)
\end{enumerate}
\hfill \mbox{\textit{AQA D1 2005 Q2 [8]}}