How fast do you have to run to get a 3.43 minute mile?

6 min, 43 s = 403 s

In the case of 4 laps around a track for a full mile, then

(403 s / 4 laps) = 100.75 s/lap =

(100.75 s/lap)(1 min/60s) = 1.68 min/lap

(0.68 min)(60s/min) = 40.8 s

So it would be 1 min and 40.8 seconds per lap.