| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2003 |
| Session | January |
| Marks | 10 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Find missing early/late times |
| Difficulty | Moderate -0.8 This is a standard D1 critical path analysis question requiring routine application of taught algorithms: finding earliest/latest times, identifying critical path, and basic scheduling. Parts (a)-(c) are direct recall/observation, while part (d) requires some trial-and-error scheduling but follows standard textbook methods with no novel problem-solving insight needed. |
| Spec | 7.05b Forward and backward pass: earliest/latest times, critical activities7.05d Latest start and earliest finish: independent and interfering float |
\includegraphics{figure_3}
A project is modelled by the activity network in Fig. 3. The activities are represented by the arcs. One worker is required for each activity. The number in brackets on each arc gives the time, in hours, to complete the activity. The earliest event time and the latest event time are given by the numbers in the left box and right box respectively.
\begin{enumerate}[label=(\alph*)]
\item State the value of $x$ and the value of $y$.
[2]
\item List the critical activities.
[2]
\item Explain why at least 3 workers will be needed to complete this project in 38 hours.
[2]
\item Schedule the activities so that the project is completed in 38 hours using just 3 workers. You must make clear the start time and finish time of each activity.
[4]
\end{enumerate}
\hfill \mbox{\textit{Edexcel D1 2003 Q5 [10]}}