How do I schedule task with two predecessors based on latest finish date

Question

I have a task (row 100) which have two predecessors, row 20 and row 30. As it is now, row 100 starts 4 weeks after row 20 has finished and 4 weeks after row 30 has finished. Is it possible for MS Project to automatically schedule after which one of the two tasks that finishes last. So for example if row 30 is delayed with two weeks, I want row 100 to be rescheduled so it still starts 4 weeks after row 30 has finished (and now 6 weeks after row 20 has finished). How do I do this in MS Project?

Answer 1

Yes. On task 100 you would add both task 20 and task 30 as predecessors, with a finish-to-start relationship and 20 days (4 weeks) of lag. Once added, the earliest task 100 will start is 4 weeks after the latest finish of tasks 20 and 30.