7.

\begin{figure}[h]
\begin{center}
  \includegraphics[alt={},max width=\textwidth]{bd6edbd4-1ec0-4c7e-bd39-b88f96bf52fb-8_752_1445_210_287}
\captionsetup{labelformat=empty}
\caption{Figure 7}
\end{center}
\end{figure}

Figure 7 is the activity network relating to a building project. The activities are represented by the arcs. The number in brackets on each arc gives the time to complete the activity. Each activity requires one worker.

The project must be completed in the shortest possible time.
\begin{enumerate}[label=(\alph*)]
\item Explain the reason for the dotted line from event 4 to event 6 as shown in Figure 7.\\
(2)
\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 Calculate the total float for activity G. You must make the numbers you use in your calculation clear.
\item Draw a Gantt chart for this project on the grid provided in the answer book.
\item State the activities that must be happening at time 5.5
\item Use your Gantt chart to determine the minimum number of workers needed to complete the project in the minimum time. You must justify your answer.
\end{enumerate}

\hfill \mbox{\textit{Edexcel D1 2013 Q7 [16]}}