6.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{6b51f3a0-0945-4254-8c63-20e1371e9e3a-07_748_1419_269_324}
\captionsetup{labelformat=empty}
\caption{Figure 4}
\end{center}
\end{figure}

A project is modelled by the activity network shown in Figure 4. The activities are represented by the arcs. The number in brackets on each arc gives the time, in days, to complete the corresponding 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 the late event times.
\item State the critical activities.
\item Draw a cascade (Gantt) chart for this project on the grid in the answer book.
\item Use your cascade chart to determine the minimum number of workers needed to complete the project in the shortest possible time. You must make specific reference to times and activities. (You do not need to provide a schedule of the activities.)
\end{enumerate}

\hfill \mbox{\textit{Edexcel D1 2018 Q6 [11]}}