Activity X has an FS relationship with a 1-day lag with succeeding Activity Y. Activity X also has a SS relationship with a 5-day lag with succeeding Activity Z. Assume that Activity X has no other immediate succeeding relationships. Given the following: Activity Y: Late Start is Day 11; Late Finish is Day 15 Activity Z: Late Start is Day 11; Late Finish is Day 15 Activity X: Duration is 5 days. Calculate Activity X's Late Start and Finish dates.( Assume: Duration = finish date minus start date + 1)

Can someone please explain the logic behind this?