how do I set a duration based on two linked tasks?

[Randy Rivard]

I need to have a task start three days before task X and end at the same time
as task y. When I do this in project it shows a duration of one day (end
date of y) and does not want to move the start date out without manually
entering in the duration of which I prefer not to do in the event one of the
linked tasks moves around.

Note that it's okay for the duration of this task to change as the linked
tasks moves around.

Thanks!
Randy

 

[Gérard Ducouret]

Hello Randy,
What you want to do is a hammock task. Look at the FAQ 19:
http://project.mvps.org/faqs.htm#Hammock Tasks
You may have to add a milestone which "starts three days before task X"

Gérard Ducouret