Float characteristics on the critical path In Critical Path Method (CPM), a critical activity’s float value is equal to what?
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Amaximum float
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Bminimum float
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Czero float
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Dnone of these
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E
Answer
Correct Answer: zero float
Explanation
Introduction / Context:Float (or slack) measures scheduling flexibility. Activities lying on the critical path control the project duration; any delay on these activities delays the entire project. Understanding float helps managers prioritise resources and monitor risks effectively.
Given Data / Assumptions:
- CPM network with defined earliest and latest event/activity times.
- Critical path is the sequence with the longest total duration.
- Critical activities are those with no scheduling leeway.
Concept / Approach:Total float = latest finish minus earliest finish (or latest start minus earliest start). For a critical activity, earliest and latest times coincide, so float = 0. This reflects that the activity must start/finish exactly as planned to avoid impacting project completion.
Step-by-Step Solution:Recognize that critical path length equals project duration.On critical activities, earliest and latest times are equal.Therefore, float = 0 for every critical activity.
Verification / Alternative check:Forward/backward pass computations in any CPM example will show float values zero on the identified critical path, confirming the rule.
Why Other Options Are Wrong:Maximum/Minimum float: Critical activities have no leeway; the float cannot be positive.None of these: Incorrect because the correct value is exactly zero.
Common Pitfalls:
- Confusing “near-critical” (very low float) with “critical.”
- Assuming float exists because of resource levelling; CPM float is purely time-based between earliest and latest values.
Final Answer:zero float