| Exam Board | AQA |
|---|---|
| Module | D2 (Decision Mathematics 2) |
| Year | 2009 |
| Session | June |
| Marks | 12 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Effect of activity delay/change |
| Difficulty | Moderate -0.8 This is a standard Critical Path Analysis question requiring routine application of well-defined algorithms (forward pass, backward pass, identifying critical path) followed by a straightforward recalculation when one activity duration changes. The multi-part structure and computational steps add some length, but no novel problem-solving or insight is required—it's textbook application of the CPA method. |
| Spec | 7.05a Critical path analysis: activity on arc networks7.05b Forward and backward pass: earliest/latest times, critical activities7.05c Total float: calculation and interpretation7.05d Latest start and earliest finish: independent and interfering float |
| Activity | Immediate Predecessors | Duration (days) |
| A | - | 5 |
| B | - | 3 |
| C | - | 2 |
| D | A, \(B\) | 4 |
| E | \(B , C\) | 1 |
| \(F\) | D | 2 |
| G | E | 9 |
| H | \(F , G\) | 1 |
| I | \(H\) | 6 |
| \(J\) | \(H\) | 5 |
| \(K\) | \(I , J\) | 2 |
| Answer | Marks | Guidance |
|---|---|---|
| - A row of numbers and unicode placeholders: `1 | (cid:1)4 | (cid:1)1 |
| - Another incomplete row: `1 | K | T |
| - A final row: `L | T | 8` |
I appreciate you sharing this content, but the extracted material you've provided doesn't appear to be a legible or complete mark scheme. The text shows:
- A row of numbers and unicode placeholders: `1 | (cid:1)4 | (cid:1)1 | (cid:1)k | 0 | 0 | 0`
- Another incomplete row: `1 | K | T | 7`
- A final row: `L | T | 8`
This doesn't contain enough context or complete marking points to clean up meaningfully. It appears either:
- The extraction was corrupted
- The source material wasn't fully captured
- The format is incomplete
Could you please provide the full, original mark scheme content? I'd be happy to clean it up once I can see the complete marking criteria with proper context.1 [Figure 1, printed on the insert, is provided for use in this question.]\\
A decorating project is to be undertaken. The table shows the activities involved.
\begin{center}
\begin{tabular}{|l|l|l|}
\hline
Activity & Immediate Predecessors & Duration (days) \\
\hline
A & - & 5 \\
\hline
B & - & 3 \\
\hline
C & - & 2 \\
\hline
D & A, $B$ & 4 \\
\hline
E & $B , C$ & 1 \\
\hline
$F$ & D & 2 \\
\hline
G & E & 9 \\
\hline
H & $F , G$ & 1 \\
\hline
I & $H$ & 6 \\
\hline
$J$ & $H$ & 5 \\
\hline
$K$ & $I , J$ & 2 \\
\hline
\end{tabular}
\end{center}
\begin{enumerate}[label=(\alph*)]
\item Complete an activity network for the project on Figure 1.
\item On Figure 1, indicate:
\begin{enumerate}[label=(\roman*)]
\item the earliest start time for each activity;
\item the latest finish time for each activity.
\end{enumerate}\item State the minimum completion time for the decorating project and identify the critical path.
\item Activity $F$ takes 4 days longer than first expected.
\begin{enumerate}[label=(\roman*)]
\item Determine the new earliest start time for activities $H$ and $I$.
\item State the minimum delay in completing the project.
\end{enumerate}\end{enumerate}
\hfill \mbox{\textit{AQA D2 2009 Q1 [12]}}