| Exam Board | OCR MEI |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2010 |
| Session | January |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Calculate early and late times |
| Difficulty | Easy -1.2 This is a straightforward application of standard Critical Path Analysis algorithms with only 5 activities and simple precedence relationships. Drawing the network and calculating early/late times using the forward and backward pass are routine procedures taught directly in D1, requiring no problem-solving insight beyond following the algorithm. |
| Spec | 7.05a Critical path analysis: activity on arc networks7.05b Forward and backward pass: earliest/latest times, critical activities |
| Activity | Duration (mins) | Immediate predecessors |
| A | 3 | - |
| B | 2 | - |
| C | 3 | A |
| D | 5 | A, B |
| E | 1 | C |
1 The table shows the activities involved in a project, their durations and their precedences.
\begin{center}
\begin{tabular}{|l|l|l|}
\hline
Activity & Duration (mins) & Immediate predecessors \\
\hline
A & 3 & - \\
\hline
B & 2 & - \\
\hline
C & 3 & A \\
\hline
D & 5 & A, B \\
\hline
E & 1 & C \\
\hline
\end{tabular}
\end{center}
(i) Draw an activity on arc network for these activities.\\
(ii) Mark on your diagram the early time and the late time for each event. Give the critical activities.
\hfill \mbox{\textit{OCR MEI D1 2010 Q1 [8]}}