| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2014 |
| Session | June |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Explain dummy activities |
| Difficulty | Moderate -0.5 This is a standard D1 critical path analysis question requiring students to draw an activity network with dummies and explain their necessity. While it requires understanding of precedence relationships and dummy activities, it follows a routine algorithmic approach taught in all D1 courses with no novel problem-solving required. The explanation part is straightforward once the network is correctly drawn. |
| Spec | 7.05a Critical path analysis: activity on arc networks |
| Activity | Immediately preceding activities |
| \(A\) | - |
| B | - |
| C | - |
| D | A, \(C\) |
| E | B |
| \(F\) | E |
| G | A |
| \(H\) | \(D , F\) |
| I | \(D , F\) |
| J | H, I |
6. (i) Draw the activity network described in the precedence table below, using activity on arc and the minimum number of dummies.
\begin{center}
\begin{tabular}{|l|l|}
\hline
Activity & Immediately preceding activities \\
\hline
$A$ & - \\
\hline
B & - \\
\hline
C & - \\
\hline
D & A, $C$ \\
\hline
E & B \\
\hline
$F$ & E \\
\hline
G & A \\
\hline
$H$ & $D , F$ \\
\hline
I & $D , F$ \\
\hline
J & H, I \\
\hline
\end{tabular}
\end{center}
(ii) Explain why each of your dummies is necessary.\\
\hfill \mbox{\textit{Edexcel D1 2014 Q6 [7]}}