Final answer:
The expected completion time of the critical path is determined by the sum of the durations of all the activities on that path.
Step-by-step explanation:
The critical path is the longest duration path through a project network, which determines the expected completion time of the project. It represents the sequence of activities that must be completed in order to finish the project in the shortest amount of time. The expected completion time of the critical path is the sum of the durations of all the activities on that path.