The answer is C. 20.3 miles per hour.
In order to solve this, we have to first convert our time into hours. We start with 11 seconds, but need to convert to hours. Since there are 3600 seconds in an hour, we need to divide by that unit rate.
11 seconds/3600 = .00305 hours
Now we need to convert our meters into miles. The problem lets us know that there are 1609 meters in a mile, so we need to divide the 100 meters by 1609.
100 meters/1609 = .0621 miles.
Now to find miles per hour, we divide the miles we got by the hours.
.00305 miles/ .0621 miles = 20.3 miles per hour.
