5 Following a promotion at work, Khalid needs to clear out his office to move to a different building. The activities involved, their durations (in hours) and immediate predecessors are listed in the table below. You may assume that some of Khalid's friends will help him and that once an activity is started it will be continued until it is completed.
| Activity | Duration (hours) | Immediate predecessors |
| A | Sort through cupboard and throw out rubbish | 4 | - |
| B | Get packing boxes | 1 | - |
| C | Sort out items from desk and throw out rubbish | 3 | - |
| D | Pack remaining items from cupboard in boxes | 2 | \(A\), \(B\) |
| E | Put personal items from desk into briefcase | 0.5 | C |
| \(F\) | Pack remaining items from desk in boxes | 1.5 | \(B , C\) |
| G | Take certificates down and put into briefcase | 1 | - |
| H | Label boxes to be stored | 0.5 | D, F |
- Represent this project using an activity network.
- Carry out a forward pass and a backward pass through the activity network, showing the early event time and late event time at each vertex of your network. State the minimum project completion time and list the critical activities.
- How much longer could be spent on sorting the items from the desk and throwing out the rubbish (activity \(C\) ) without it affecting the overall completion time?
Khalid says that he needs to do activities \(A , C , E\) and \(G\) himself. These activities take a total of 8.5 hours.
- By considering what happens if Khalid does \(A\) first, and what happens if he does \(C\) first, show that the project will take more than 8.5 hours.
- Draw up a schedule to show how just two people, Khalid and his friend Mia, can complete the project in 9 hours. Khalid must do \(A , C , E\) and \(G\) and activities cannot be shared between Khalid and Mia. [2]