A small project has the following activities, with their durations (in days) and immediate predecessors:
| Activity | Predecessor(s) | Duration (days) |
|---|---|---|
| A | — | 4 |
| B | — | 3 |
| C | A | 2 |
| D | B | 5 |
| E | C, D | 3 |
Draw the logical structure of the network (describe it), find the earliest and latest event times, and identify the critical path and the project's minimum completion time.
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Start your 14-day free trial to unlock the full solution →Step 1 — Set up the network's events. Event 1 (start) → A and B both begin here (no predecessors). A (4 days) finishes at event 2; C (predecessor A) runs from event 2 to event 3 (2 days). B (3 days) finishes at event 2 as well only if it shares a tail with A — but since A and B have no shared predecessor relationship stated, and D depends on B while C depends on A, event 1 is the common start for both A and B, with A leading to the event where C starts, and B leading to the event where D starts; C and D both feed into event 4, from which E (3 days) runs to the final event 5.
Step 2 — Forward pass (earliest event times, ). (start). (after A). Also treat B's completion event similarly: at B's finish . runs from A's finish, duration 2: reaches . runs from B's finish, duration 5: reaches . Both C and D feed into the event before E, so that event's earliest time is the larger of the two incoming paths: . Finally (project's earliest finish).
Step 3 — Identify the two paths from start to finish explicitly. Path A→C→E: duration days. Path B→D→E: duration days.
Step 4 — Backward pass (latest event times, ), starting from . Working back through E (duration 3): the event before E must have . Working back along D (duration 5) from that event: B's finish event needs . Working back along C (duration 2) from the same shared event: A's finish event needs . …
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