2 [Figures 1 and 2, printed on the insert, are provided for use in this question.]\\
Figure 1 shows the activity network and the duration in days of each activity for a particular project.
\begin{enumerate}[label=(\alph*)]
\item On Figure 1:
\begin{enumerate}[label=(\roman*)]
\item find the earliest start time for each activity;
\item find the latest finish time for each activity.
\end{enumerate}\item Find the critical paths and state the minimum time for completion.
\item The number of workers required for each activity is shown in the table.

\begin{center}
\begin{tabular}{ | l | c | c | c | c | c | c | c | c | c | c | }
\hline
Activity & $A$ & $B$ & $C$ & $D$ & $E$ & $F$ & $G$ & $H$ & $I$ & $J$ \\
\hline
\begin{tabular}{ l }
Number of \\
workers required \\
\end{tabular} & 3 & 3 & 4 & 2 & 3 & 4 & 1 & 2 & 2 & 5 \\
\hline
\end{tabular}
\end{center}
\begin{enumerate}[label=(\roman*)]
\item Given that each activity starts as early as possible and assuming that there is no limit to the number of workers available, draw a resource histogram for the project on Figure 2, indicating clearly which activities take place at any given time.
\item It is later discovered that there are only 6 workers available at any time. Explain why the project will overrun, and use resource levelling to indicate which activities need to be delayed so that the project can be completed with the minimum extra time. State the minimum extra time required.
\end{enumerate}\end{enumerate}

\hfill \mbox{\textit{AQA D2 2009 Q2 [14]}}