Final answer:
If the actual duration of a task entered in Microsoft Project exceeds the planned duration, Microsoft Project generally assumes a delayed finish, hence extending the finish date of the task.
Step-by-step explanation:
When you enter an actual duration for a task in Microsoft Project that is longer than the planned duration, the software typically assumes a delayed finish. This is because the task took more time to complete than was initially scheduled. Microsoft Project then updates the task's finish date to reflect this additional time while keeping the start date intact unless constraints or dependencies dictate otherwise. Consequently, the extension in the actual duration results in pushing out the finish date which implies a delay in the project's schedule.