| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2017 |
| Session | June |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Draw activity network from table |
| Difficulty | Moderate -0.3 This is a straightforward activity network construction requiring systematic application of precedence rules and dummy arcs. While it requires careful attention to dependencies (particularly E, F, G all depending on C and D, and the multiple dependencies for H and I), it follows standard D1 procedures without requiring novel problem-solving or complex logical reasoning beyond textbook methods. |
| Spec | 7.05a Critical path analysis: activity on arc networks |
| Activity | Immediately preceding activities |
| A | - |
| B | - |
| C | A |
| D | A |
| E | C, D |
| F | C, D |
| G | C, D |
| H | B, E |
| I | B, E, F, G |
| J | G |
| K | G |
| Answer | Marks | Guidance |
|---|---|---|
| Answer/Scheme | Marks | Guidance |
| M1 A1 A1 A1 A1 | 5 marks |
| Answer/Scheme | Marks | Guidance |
|---|---|---|
| | M1 A1 A1 A1 A1 | **5 marks** |
**Notes for Question 7:**
Condone lack of, or incorrect, numbered events throughout and arcs which cross one another. "Dealt with correctly" means that the activity starts from the correct event but need not necessarily finish at the correct event, e.g. "I dealt with correctly" requires the correct immediate precedences for this activity, i.e. B and E labelled correctly and leading into the same node and H starting from that node but not necessarily H leading into the end node. **Activity on node is M0**
**Ignore incorrect or lack of arrows on the activities for the first four marks only**
M1: 7 activities (labelled on arc), one start, at least one dummy placed and activites A, B and D dealt with correctly
1A1: First dummy correct (+ arrow) and activities E, F and G dealt with correctly
2A1: Second and third dummies correct (+ arrows) and activities H and I dealt with correctly
3A1: Fourth dummy correct (+ arrow) and activities J and K dealt with correctly
4A1: CSO (all four previous marks must have been awarded) - all arrows present and correctly placed with one finish and no additional dummies. Please check all arcs carefully for arrows
Note that there are a number of additional valid solutions in which the candidate may deal with the dummies with regards to activities C,D and J,K so it is vital that the diagram is checked carefully for any other equally acceptable/valid solution7. Draw the activity network described in this precedence table, using activity on arc and dummies only where necessary.
\begin{center}
\begin{tabular}{|l|l|}
\hline
Activity & Immediately preceding activities \\
\hline
A & - \\
\hline
B & - \\
\hline
C & A \\
\hline
D & A \\
\hline
E & C, D \\
\hline
F & C, D \\
\hline
G & C, D \\
\hline
H & B, E \\
\hline
I & B, E, F, G \\
\hline
J & G \\
\hline
K & G \\
\hline
\end{tabular}
\end{center}
\hfill \mbox{\textit{Edexcel D1 2017 Q7 [5]}}