Seconds is a unit of time, mile is a unit of length; you can't convert one to the other.
To solve speed problems, use the formula distance = speed x time. Solving for time: time = distance / speed.
300 seconds per mile = 17.6 feet per second
1 / 42 mph = 0.02381 hours per mile0.02381 hours per mile x 3600 sec. per hour = 85.7143 seconds per mile.
The number of seconds in a mile varies according to the speed that you are traveling. For example, if you are going 60 miles per hour, then there are 60 seconds in each mile.
This equates to a pace of 15 minutes 3.2 seconds per mile.
k seconds per mile = 3600/k miles per hour.
If you run a mile in 4 minutes and 32 seconds, you average 13.235 miles per hour.
8.726 miles per hour.
1 mile/50 sec * 3600 sec/hr = 72 mph
1 mile in 30 seconds is 120 miles per hour!
Convert the time to hours. Then divide the distance (1 mile in this case) by the time.
(1 mile / 75 seconds) x (3,600 seconds / hour) = 48 miles per hour
109.09 mph