Depending on the circumstances they may almost treat it as such since they get to see all the grades. If you had an F that was a long time ago(10+ yrs) but you retook the course recently and Aced it then there is less stress on that F. Officially though both grades will be calculated though. Very unlikely but they could treat it as that F is almost irrelevant. If the recent A is surrounded by whole slew of As then they'll notice that you are different now than before. It also varies from school too.