# Predecessor Logic

Options

Hello, I have a Task A which I want the logic to work as to start this task when Task B finishes + Have Task A finish when Task C finishes.

Basically Task A we can start some of the work when Task B is done but it can't be finalized until Task C finishes is what I am trying to set up.

However when I set this up with Task B as a predecessor FS, Task C FF it just takes the end date of task c but does not give me the start date of when Task B fnishes. I'm assuming as the duration is overriding but I want it to dictate what the duration should be if that makes sense. So rather then the 8 days I've set , it would then show this task will span 15 days or adjust based on Task B and C.

## Answers

• ✭✭✭✭✭✭
Options

By splitting Task A into sub-tasks and making those sub-tasks children of Task A, you can achieve the desired dynamic adjustment of Task A's duration.

https://app.smartsheet.com/b/publish?EQBCT=9986ccb7004e446ca80efd7b41c6ac73

Here's how you can set it up:

Split Task A into Sub-tasks:

• Create Sub-task A1 that starts when Task B finishes.
• Create Sub-task A2 that finishes when Task C finishes. (Duration = 0)

Set Dependencies:

• Set Task B as a predecessor (Finish-to-Start, FS) to Sub-task A1.
• Set Task C as a predecessor (Finish-to-Finish, FF) to Sub-task A2.
• Roll Up Sub-tasks to Task A:
• Make Sub-tasks A1 and A2 children of Task A.
• The duration and dates of Task A will be automatically adjusted based on the start and end dates of Sub-tasks A1 and A2.

By organizing Task A this way, you ensure that its duration is dynamically calculated based on the completion times of Task B and Task C, effectively meeting your scheduling needs.