A college runner set a school record of 3:59.37 in the mile run. assuming that the distance was measured accurately to five significant figures, what was the runner's average speed in kilometers per hour?

We are given that the time record in a 1 mile run is 3:59.37 where this is in the format of HH:MM

There are 3 hours 59.37 minutes. Converting every unit to hour:

3 hours + 59.37 min (1 hour / 60 minute) = 3.9895 hour

So the average speed is:

average speed = 1 mile * (1.61 km / mile) / 3.9895 hour

average speed = 0.4 km / hour