| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2016 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Draw network with specified dummies |
| Difficulty | Moderate -0.3 This is a standard D1 network drawing exercise requiring systematic application of precedence rules. While using exactly three dummies adds a constraint that requires some planning, the task is routine for students who have practiced activity-on-arc networks. It's slightly easier than average because it's primarily procedural rather than requiring problem-solving or novel insight. |
| Spec | 7.05a Critical path analysis: activity on arc networks |
| Activity | Immediately preceding activities |
| A | - |
| B | - |
| C | A |
| D | A |
| E | B |
| F | B |
| G | A, E, F |
| H | F |
| I | C |
| J | D, G |
| K | D, G |
| Answer | Marks | Guidance |
|---|---|---|
| Answer/Working | Marks | Guidance |
| Network diagram with 7 activities (labelled on arc), 1 start and 2 dummies placed | M1 | 7 activities, 1 start and 2 dummies |
| Activities A, B, C, D, E, F dealt with correctly | A1 | |
| Activities G, H and first two dummies (including arrows on dummies) dealt with correctly | A1 | "First two dummies" = those leading into event at end of E |
| Activities I, J, K dealt with correctly | A1 | |
| Final dummy correctly placed, all arrows present and correctly placed, one finish, no additional dummies | A1 CSO | All four previous marks must have been awarded |
# Question 2:
| Answer/Working | Marks | Guidance |
|---|---|---|
| Network diagram with 7 activities (labelled on arc), 1 start and 2 dummies placed | M1 | 7 activities, 1 start and 2 dummies |
| Activities A, B, C, D, E, F dealt with correctly | A1 | |
| Activities G, H and first two dummies (including arrows on dummies) dealt with correctly | A1 | "First two dummies" = those leading into event at end of E |
| Activities I, J, K dealt with correctly | A1 | |
| Final dummy correctly placed, **all** arrows present and correctly placed, one finish, no additional dummies | A1 CSO | All four previous marks must have been awarded |
---2. Draw the activity network described in the precedence table below, using activity on arc and exactly three dummies.
\begin{center}
\begin{tabular}{|l|l|}
\hline
Activity & Immediately preceding activities \\
\hline
A & - \\
\hline
B & - \\
\hline
C & A \\
\hline
D & A \\
\hline
E & B \\
\hline
F & B \\
\hline
G & A, E, F \\
\hline
H & F \\
\hline
I & C \\
\hline
J & D, G \\
\hline
K & D, G \\
\hline
\end{tabular}
\end{center}
\hfill \mbox{\textit{Edexcel D1 2016 Q2 [5]}}