Divide the traveled distance over the total time it took to travel it to find the rate in miles per minute:
[tex]\frac{1\text{ mile}}{1+\frac{1}{4}\text{ minutes}}=\frac{1\text{ mile}}{1.25\text{ minutes}}=0.8\text{ miles per minute}[/tex]Since each hour has 60 minutes, multiply that rate by 60 to find how fast is Seth in miles per hour:
[tex]0.8\times60=48[/tex]Therefore, the rate of distance to time for Seth is:
[tex]48\text{ miles per hour}[/tex]