Bởi vì "làm cho đồ uống" mất 30 phút và nhiệm vụ của Erica mất 20 phút và bốn phút, "làm cho đồ uống" đại diện con đường quan trọng trong dự án này, do đó, các đường màu đen giữa hoạt động đầu tiên và thứ hai của Bill. | The relationships between the boxes are indicated with dark or fine lines. For example prepare dessert and prepare casserole are connected by a thin line. Bill s task make drinks connects to load up food basket with a thick line which we will get to in a moment. Both Bill s and Erica s tasks lead to fill up food basket. 2. Because make drinks takes 30 minutes and Erica s tasks take 20 minutes and four minutes respectively make drinks represents the critical path in this project hence the black line between Bill s first and second activity. Erica s path has six minutes of slack built in. If she starts a few minutes late or takes a minute or two between tasks she will still finish before Bill as long as her total slack does not exceed six minutes. Conceivably she could take her time on each project adding a minute or two to each and still finish before Bill and if her slack equals six minutes she will finish at the same time as Bill. 2. The critical path for the entire project as depicted above can be traced by 1. Noting which tasks occur simultaneously. 2. Noting which ones take longer. 3. Routing the critical path through them. 4. Summing the entire length of the critical path. In the preceding case the entire project would take 100 minutes. It all sounds straightforward so far doesn t it 5. For this or any other type of project look at the earliest times that critical tasks need to start. Then determine the earliest times that noncritical paths could start. Column 2 of the next figure indicates the earliest start times for all of Bill s and Erica s individual as well as combined tasks. Roster of events with start stop and slack time. Task Earíy start Late Start Slack Make drinks 0 0 0 Prepare sandwiches 0 6 6 Prepare fruit 20 26 6 Prepare basket 30 30 0 Gather blankets 34 36 2 Gather sports gear 34 34 0 Load car 40 40 0 Get gas 48 48 0 Drive Io outing 60 60 0 Column 3 shows the latest start times for Tasks 2 3 and 6 the first two handled by Erica and the latter .
