Network Analysis MCQ with answer and solution

Concept

Definition of critical event in CPM network

Formula

Slack = T_L - T_E = 0

Step-by-step solution

1. In network analysis, event slack is defined as S = T_L - T_E (Latest allowable time - Earliest expected time). 2. Critical path connects events where no scheduling leeway exists, meaning slack is zero. 3. An event with zero slack cannot be delayed without delaying the entire project completion date. 4. Therefore, option B ('An event with zero slack') is correct. Answer: B

Explanation

In the Critical Path Method (CPM), an event is critical if its event slack is zero (Slack = 0), which occurs when the latest allowable occurrence time equals the earliest expected occurrence time (T_L = T_E). Critical events lie along the critical path of the project network.

Why the other options are wrong

A) An event with maximum slack is the least critical event in the project network. C) Negative float indicates a supercritical condition where project deadline is already violated, not the standard critical event definition. D) Events represent points in time and have zero duration, not maximum duration.

Shortcut

Critical Event = Zero Slack (T_L = T_E); Critical Activity = Zero Float.

Common mistake

Confusing event slack with activity float, or assuming critical events have maximum slack instead of zero slack.