| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2014 |
| Session | June |
| Marks | 11 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Critical Path Analysis |
| Type | Calculate lower bound for workers |
| Difficulty | Standard +0.3 This is a standard Critical Path Analysis question covering routine D1 techniques: finding early/late times, calculating float, determining lower bound for workers, and scheduling. All parts follow textbook procedures with no novel problem-solving required, making it slightly easier than average. |
| Spec | 7.05a Critical path analysis: activity on arc networks7.05b Forward and backward pass: earliest/latest times, critical activities7.05c Total float: calculation and interpretation7.05d Latest start and earliest finish: independent and interfering float7.05e Cascade charts: scheduling and effect of delays |
7.
\begin{figure}[h]
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\includegraphics[alt={},max width=\textwidth]{23cc3c59-35d8-4120-9965-952c0ced5b3d-8_620_1221_251_427}
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\caption{Figure 5}
\end{center}
\end{figure}
A project is modelled by the activity network shown in Figure 5. The activities are represented by the arcs. The number in brackets on each arc gives the time, in days, to complete the activity. Each activity requires one worker. The project is to be completed in the shortest possible time.
\begin{enumerate}[label=(\alph*)]
\item Complete Diagram 1 in the answer book to show the early event times and late event times.
\item Calculate the total float for activity D. You must make the numbers you use in your calculation clear.
\item Calculate a lower bound for the number of workers needed to complete the project in the minimum time. You must show your working.
The project is to be completed in the minimum time using as few workers as possible.
\item Schedule the activities using Grid 1 in the answer book.
\end{enumerate}
\hfill \mbox{\textit{Edexcel D1 2014 Q7 [11]}}