| Exam Board | Edexcel |
|---|---|
| Module | FD1 (Further Decision 1) |
| Year | 2019 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Identify guaranteed critical activities |
| Difficulty | Moderate -0.5 This is a straightforward application of standard Critical Path Analysis techniques from Decision Maths. Part (a) requires drawing an activity network with dummies (routine but requires care), and part (b) asks for the critical path when all activities have equal duration, which makes it simpler than typical CPA problems since you only need to count activities rather than sum durations. This is easier than average A-level questions due to the equal-duration simplification and being a direct application of a standard algorithm. |
| Spec | 7.05a Critical path analysis: activity on arc networks |
| Activity | Immediately preceding activities |
| A | - |
| B | - |
| C | - |
| D | A |
| E | C |
| F | B, C, D |
| G | A |
| H | B, C, D |
| I | B, C, D, G |
| J | B, C, D, G |
| K | E, H |
| Answer | Marks | Guidance |
|---|---|---|
| Answer/Working | Mark | Guidance |
| At least nine activities (labelled on arc), one start, at least two dummies placed | M1 | Activity on node is M0; ignore incorrect/lack of arrows for first four marks only |
| Activities A, B, C, D, E, G dealt with correctly | A1 | |
| Activities F, H and first two dummies + arrows dealt with correctly | A1 | First two dummies are those required at event at end of activity B |
| Activities I, J and K dealt with correctly (I and J can start directly after end of G) | A1 | |
| CSO - Final dummy + arrow; all arrows present for every activity with one finish and no additional dummies | A1 | Not a unique solution; if no arrows on dummies then M1A1 max; unnecessary correct dummies penalised only on final A mark |
| Answer | Marks | Guidance |
|---|---|---|
| Answer/Working | Mark | Guidance |
| Critical path: ADHK | B1 | CAO (ADHK only) |
# Question 5:
## Part (a):
| Answer/Working | Mark | Guidance |
|---|---|---|
| At least nine activities (labelled on arc), one start, at least two dummies placed | M1 | Activity on node is M0; ignore incorrect/lack of arrows for first four marks only |
| Activities A, B, C, D, E, G dealt with correctly | A1 | |
| Activities F, H and first two dummies + arrows dealt with correctly | A1 | First two dummies are those required at event at end of activity B |
| Activities I, J and K dealt with correctly (I and J can start directly after end of G) | A1 | |
| CSO - Final dummy + arrow; all arrows present for every activity with one finish and no additional dummies | A1 | Not a unique solution; if no arrows on dummies then M1A1 max; unnecessary correct dummies penalised only on final A mark |
## Part (b):
| Answer/Working | Mark | Guidance |
|---|---|---|
| Critical path: ADHK | B1 | CAO (ADHK only) |
---5.
\begin{center}
\begin{tabular}{|l|l|}
\hline
Activity & Immediately preceding activities \\
\hline
A & - \\
\hline
B & - \\
\hline
C & - \\
\hline
D & A \\
\hline
E & C \\
\hline
F & B, C, D \\
\hline
G & A \\
\hline
H & B, C, D \\
\hline
I & B, C, D, G \\
\hline
J & B, C, D, G \\
\hline
K & E, H \\
\hline
\end{tabular}
\end{center}
(a) Draw the activity network described in the precedence table above, using activity on arc. Your activity network must contain only the minimum number of dummies.
Given that all the activities shown in the precedence table have the same duration, (b) state the critical path for the network.\\
\hfill \mbox{\textit{Edexcel FD1 2019 Q5 [6]}}