Typically you play one octave in quarters, two octaves in eight notes, three octaves in triplet, four octaves in sixteenth notes. This is good, because you start off slow (quarter notes) and get fast with the changing rythmn, so that you don't have to jump right in to fast.
I'm not getting in to an arguement, please don't comment on this, Ed. Scales are important to play well, to show your auditioner that you have control and can play freely and even. If you fumble up a piece but play excellent scales, that will help sway the commitee. You have shown them your technical stength. T