CPM time definitions: Earliest finish time (EF) of an activity equals which time relationship?

Question

Solve this multiple-choice question and choose the correct option.

Accepted Answer

Introduction / Context:Forward and backward passes in CPM compute start/finish times to identify project duration and floats. Correct formulas are key to accurate networks. Given Data / Assumptions: Each activity has a deterministic duration, d. Earliest start (ES) is known from predecessors. Finish times consider end-of-activity events. Concept / Approach:The forward pass determines the earliest times. For any activity, the earliest time it can finish is simply its earliest start plus its own duration: EF = ES + d. Backward pass analogously uses latest finish and duration to compute latest start: LS = LF - d. Step-by-Step Solution: Find ES from the maximum EF of all immediate predecessors.Compute EF = ES + d.Propagate EF values to successors to determine their ES.Later, compute LS = LF - d during the backward pass for floats. Verification / Alternative check:Test with d = 5, ES = 3: EF = 8. Any other relation gives a wrong value, confirming option (a). Why Other Options Are Wrong:Subtracting duration from ES or adding duration to LF mixes forward and backward pass logic. Common Pitfalls:Ignoring calendar constraints; misinterpreting start-to-start or finish-to-finish relationships that modify simple ES/EF logic. Final Answer:Earliest start time + duration of activity

CPM time definitions: Earliest finish time (EF) of an activity equals which time relationship?

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