| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Calculate early and late times |
| Difficulty | Moderate -0.8 This is a standard textbook exercise in Critical Path Analysis requiring mechanical application of forward and backward pass algorithms. The procedures are routine and well-practiced, with no problem-solving insight needed—students simply follow the algorithm systematically through the network. |
| Spec | 7.05a Critical path analysis: activity on arc networks7.05b Forward and backward pass: earliest/latest times, critical activities |
| Answer | Marks | Guidance |
|---|---|---|
| (a) | M2 A3 | |
| (b) B, F, H, M, O, P | M1 A1 | |
| (c) 47 days | A1 | (8) |
**(a)** | M2 A3 |
**(b)** B, F, H, M, O, P | M1 A1 |
**(c)** 47 days | A1 | (8)
---3. This question should be answered on the sheet provided.
\begin{figure}[h]
\begin{center}
\includegraphics[alt={},max width=\textwidth]{6c6b7934-ab46-4a87-8a11-f99bf9a5d743-03_744_1524_319_315}
\captionsetup{labelformat=empty}
\caption{Fig. 2}
\end{center}
\end{figure}
Figure 2 shows an activity network. The nodes represent events and the arcs represent the activities. The number in each bracket gives the time, in days, needed to complete the activity.
\begin{enumerate}[label=(\alph*)]
\item Calculate the early and late times for each event using appropriate forward and backward scanning.\\
(5 marks)
\item Hence, determine the activities which lie on the critical path.
\item State the minimum number of days needed to complete the entire project.
\end{enumerate}
\hfill \mbox{\textit{Edexcel D1 Q3 [8]}}