Dave Fletcher was able to determine the activity times for constructing his laser scanning machine Fletcher would like to determine ES EF LS LF and slack for each activity The total project completion time and the critical path should also be determined Here are the activity times Q Activity Time weeks Immediate Predecessor s Activity Time weeks Immediate Predecessor s A B C D 7 6 4 3 A A Dave s earliest start ES and earliest finish EF are Activity ES EFG H EF 7 4 5 11 6 B B C E D F