Using the data in the network diagram above, calculate the Earliest Start Times (EST) and Latest Finishing Times (LFT) for each activity and identify the critical path.
- Edexcel - A-Level Business - Question 2 - 2017 - Paper 2
Question 2
Using the data in the network diagram above, calculate the Earliest Start Times (EST) and Latest Finishing Times (LFT) for each activity and identify the critical pa... show full transcript
Worked Solution & Example Answer:Using the data in the network diagram above, calculate the Earliest Start Times (EST) and Latest Finishing Times (LFT) for each activity and identify the critical path.
- Edexcel - A-Level Business - Question 2 - 2017 - Paper 2
Step 1
Calculate the Earliest Start Times (EST)
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Answer
Activity A: Since it has no predecessor, EST = 0.
Activity B: EST = 0 (A must finish before B can start).
Activity C: EST = max(EST of A) = 0.
Activity D: EST = max(EST of B) = 3.
Activity E: EST = max(EST of C) = 3.
Activity F: EST = max(EST of D) = 11.
Activity G: EST = max(EST of E) = 14.
Activity H: EST = max(EST of F and G) = 18.
Step 2
Calculate the Latest Finishing Times (LFT)
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Activity H: LFT = 18 (as it is the final activity).
Activity F: LFT = LFT(H) = 18 - 5 = 13.
Activity G: LFT = LFT(H) = 18 - 4 = 14.
Activity D: LFT = LFT(F) = 13 - 3 = 10.
Activity E: LFT = LFT(G) = 14 - 3 = 11.
Activity B: LFT = 10 (as it depends on D).
Activity C: LFT = 11 (as it depends on E).
Activity A: LFT = min(LFT(B), LFT(C)) = 10.
Step 3
Identify the Critical Path
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The critical path includes the activities that have the same EST and LFT. Here, the critical path is A → B → D → F → H, as these activities have no flexibility in their scheduling.