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These are the user uploaded subtitles that are being translated: 1 1 00:00:00,980 --> 00:00:03,480 Here's the Backward Pass. 2 2 00:00:03,480 --> 00:00:05,630 We start at the end of the project 3 3 00:00:05,630 --> 00:00:07,900 and scan backward to the beginning 4 4 00:00:07,900 --> 00:00:11,560 to find the latest everything can start and finish 5 5 00:00:11,560 --> 00:00:13,310 given the constraints of the logic. 6 6 00:00:14,690 --> 00:00:17,360 If a deliverable has more than one successor, 7 7 00:00:17,360 --> 00:00:21,330 we copy the least latest start of all the successors 8 8 00:00:21,330 --> 00:00:23,080 to the predecessor's latest finish. 9 9 00:00:24,440 --> 00:00:27,470 Then we subtract the duration from the latest finish 10 10 00:00:27,470 --> 00:00:29,603 to get the deliverable's latest start. 11 11 00:00:30,707 --> 00:00:32,260 And we write these numbers on the bottom 12 12 00:00:32,260 --> 00:00:34,310 of the deliverable to keep track of them. 13 13 00:00:36,110 --> 00:00:38,080 We start at the end of the project 14 14 00:00:38,080 --> 00:00:39,990 and already know the shortest schedule 15 15 00:00:39,990 --> 00:00:41,840 is 34 days in duration, 16 16 00:00:41,840 --> 00:00:44,720 so the latest day the training session can finish 17 17 00:00:44,720 --> 00:00:47,213 and preserve the critical path is day 34. 18 18 00:00:48,500 --> 00:00:50,980 Since we're going backward, we subtract numbers 19 19 00:00:50,980 --> 00:00:52,870 and the training session is one day in duration 20 20 00:00:52,870 --> 00:00:55,793 so the latest day it can start is 34 minus one or 33. 21 21 00:00:56,850 --> 00:00:58,860 We write the latest finish at the bottom right 22 22 00:00:58,860 --> 00:01:01,810 and the latest start at the bottom left of the deliverable. 23 23 00:01:03,170 --> 00:01:04,790 The implement new floor plan deliverable 24 24 00:01:04,790 --> 00:01:08,370 only has one successor, so the latest day it can finish, 25 25 00:01:08,370 --> 00:01:10,990 while preserving the critical path, 26 26 00:01:10,990 --> 00:01:14,423 is the latest start of that successor which is day 33. 27 27 00:01:15,930 --> 00:01:18,310 The implement new floor plan is two days in duration, 28 28 00:01:18,310 --> 00:01:22,023 so the latest it can start is 33 minus two or day 31. 29 29 00:01:23,520 --> 00:01:26,430 Since most deliverables only have one successor, 30 30 00:01:26,430 --> 00:01:28,200 we can just keep moving backward, 31 31 00:01:28,200 --> 00:01:30,490 copying the latest start to the previous 32 32 00:01:30,490 --> 00:01:32,393 latest finish for quite a while. 33 33 00:01:33,440 --> 00:01:36,260 The first time a deliverable has more than one successor 34 34 00:01:36,260 --> 00:01:38,760 is all the way back to the executive review 35 35 00:01:38,760 --> 00:01:42,690 with three successors: the new floor plan second draft, 36 36 00:01:42,690 --> 00:01:45,160 new department processes second draft, 37 37 00:01:45,160 --> 00:01:46,923 and training manual first draft. 38 38 00:01:47,970 --> 00:01:50,200 Since there is more than one successor 39 39 00:01:50,200 --> 00:01:53,160 we choose the least latest start to copy over 40 40 00:01:53,160 --> 00:01:55,970 as the latest finish, which is day 12, 41 41 00:01:55,970 --> 00:01:58,320 from the new department processes second draft. 42 42 00:01:59,460 --> 00:02:00,930 Given the logic of the project, 43 43 00:02:00,930 --> 00:02:02,840 as shown in the precedence diagram, 44 44 00:02:02,840 --> 00:02:05,929 day 12 is the latest the executive review can finish 45 45 00:02:05,929 --> 00:02:08,283 and maintain the 34 day schedule. 46 46 00:02:10,300 --> 00:02:12,850 We keep moving backward through the project. 47 47 00:02:12,850 --> 00:02:14,720 The next and only other time we have more 48 48 00:02:14,720 --> 00:02:17,730 than one successor is for the kick off meeting. 49 49 00:02:17,730 --> 00:02:21,090 So we choose the least of the successor's latest start, 50 50 00:02:21,090 --> 00:02:23,960 the least of seven, one, and 17. 51 51 00:02:23,960 --> 00:02:25,010 Copying over the one. 52 52 00:02:25,870 --> 00:02:27,920 We then subtract the kickoff meeting one day duration 53 53 00:02:27,920 --> 00:02:31,470 to determine the latest it can start, which is day zero. 54 54 00:02:31,470 --> 00:02:33,170 Since the early start and late start 55 55 00:02:33,170 --> 00:02:36,120 of the first deliverable both match at zero, 56 56 00:02:36,120 --> 00:02:38,570 this confirms we did all the arithmetic properly. 57 57 00:02:39,805 --> 00:02:43,020 Now, we've calculated the earliest everything 58 58 00:02:43,020 --> 00:02:45,870 can start and finish with the forward pass, 59 59 00:02:45,870 --> 00:02:47,720 and the latest everything can start and finish 60 60 00:02:47,720 --> 00:02:50,950 with the backward pass, which gives us everything we need 61 61 00:02:50,950 --> 00:02:53,740 to calculate the float of all the deliverables 62 62 00:02:53,740 --> 00:02:55,240 and confirm the critical path. 63 63 00:02:56,210 --> 00:02:57,293 Let's take a look. 5625