What's your mile/minute ratio?

I have a tendency to abbreviate so that could also be showed as mi/min. If you are working on a treadmill most of the time it'll tell you how long it will take you, at the current speed, to do a mile. If you do interval...well I don't know how you'd figure that out. Perhaps just pay attention to your distance and time elapsed? If there is a better way I am interested in knowing it!

What's your time?