Define "Critical path", "Slack time", "Resource Levelling" and "Dummy activity" with reference to PERT and CPM. An architect has been awarded a contract to prepare plans for an urban renewal project. The job consists of the following activities and their estimated value. Draw a critical path arrow diagram for this project, indicate the critical path and calculate the total slack and free slack for each activity. \begin{tabular}{|c|l|c|c|} \hline Job & Description & Predecessor & Expectedtimeindays \\ \hline A & Preparepreliminarysketches & NA & 2 \\ \hline B & Outlinespecifications & NA & 1 \\ \hline C & Preparedrawings & A & 3 \\ \hline D & Writespecifications & A B & 2 \\ \hline E & Run prints & C D & 1 \\ \hline F & Havespecificationsprinted & B D & 3 \\ \hline G & Assemblebidpackage & E F & 1 \\ \hline \end{tabular}