Hope this will help you.
So, you already know how long it takes him to run 100 meters,9.91 seconds.
In order to get the answer, you need to multiply 26 miles by 9.91 seconds.
The answer you would get from doing that is 257.66 minutes.
If you want to simplify it into hours, simplify it by 60 minutes.
4 hours and 29 minutes is the answer.