Question 515522
Our runner ran a mile in 4 minutes and 15 seconds.  To figure out his speed in miles per hour, we first need to convert 4 minutes and 15 seconds into hours.  There are 60 seconds in a minute, so 15 seconds is:

{{{15/60 = 0.25}}} minutes

So 4 minutes and 15 seconds is 4.25 minutes.  There are 60 minutes in an hour, so 4.25 minutes is:

{{{4.25/60}}} hours, or, to the nearest ten thousandth, 0.0708 hours.

So the runner ran 1 mile in {{{4.25/60}}} hours.  This gives us a speed of:

{{{(1)/((4.25)/(60)) = 60/4.25}}} mph, or, to the nearest hundredth, 14.12 mph.