Quick background: HS senior, previous 3 mi PR of 15:30 @ woodbridge (flat course).
Workout was run on track, 3 minute recovery between reps.
Splits: 5:10, 5:09, 5:08, 5:05, 4:55.
Averages out to about 5:05. Last year around this time I did a similar workout (same recovery but one less rep) averaging 5:12ish.
Effort was pretty up there, but still controlled & smooth the whole way. Not a hands-on-knees-and-falling-when-you-finish workout.
For simplicity's sake, assume a flat/almost-flat grass course like Woodbridge in good weather conditions.