Which type of relationship is described as a success where a successor cannot finish until a predecessor starts?

The correct answer is a start-to-start relationship. This type of relationship indicates that the start of one activity (the successor) is dependent on the start of another activity (the predecessor). Essentially, the successor cannot commence until the predecessor has begun its execution. This type of relationship illustrates a scenario where there is overlapping in the scheduling of tasks, allowing multiple tasks to kick off simultaneously.

For example, in a construction project, if one task involves pouring a foundation (the predecessor), the task of setting up the frames for the walls (the successor) can only begin once the foundation setup has started. Thus, this relationship helps in visually representing tasks that can progress in parallel but are still reliant on one another to some degree.

The other relationships—finish-to-start, start-to-finish, and finish-to-finish—have different dependent characteristics that don't fit the scenario described. In a finish-to-start relationship, the successor waits for the predecessor to complete before it starts, while in a start-to-finish relationship, the successor must start before the predecessor finishes, which contradicts the premise of a successor needing the predecessor to begin. Lastly, a finish-to-finish relationship requires both tasks to finish simultaneously, which does not relate to their starting conditions.