| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2018 |
| Session | June |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Identify guaranteed critical activities |
| Difficulty | Moderate -0.8 Part (a) is a standard network drawing exercise requiring careful dummy placement (5 marks), while part (b) requires simple logical deduction about critical path dependencies given that D is critical. This is routine D1 material testing basic understanding of critical activities with minimal problem-solving—easier than average A-level maths. |
| Spec | 7.05a Critical path analysis: activity on arc networks |
| Activity | Immediately preceding activities |
| A | - |
| B | - |
| C | - |
| D | A |
| E | D |
| F | A, B |
| G | A, B, C |
| H | A, B, C |
| I | E, F, G |
| J | E, F, G |
| K | E, F, G, H |
3.\\
\begin{enumerate}[label=(\alph*)]
\item Draw the activity network described in the precedence table below, using activity on arc and exactly four dummies.\\
(5)
\begin{center}
\begin{tabular}{|l|l|}
\hline
Activity & Immediately preceding activities \\
\hline
A & - \\
\hline
B & - \\
\hline
C & - \\
\hline
D & A \\
\hline
E & D \\
\hline
F & A, B \\
\hline
G & A, B, C \\
\hline
H & A, B, C \\
\hline
I & E, F, G \\
\hline
J & E, F, G \\
\hline
K & E, F, G, H \\
\hline
\end{tabular}
\end{center}
Given that D is a critical activity,
\item state which other activities must also be critical.\\
(2)\\
\end{enumerate}
\hfill \mbox{\textit{Edexcel D1 2018 Q3 [7]}}