I don't really know what the question is, but I'm guessing that you want this speed expressed in miles per hour.
\(\frac{1\text{ mile}}{0.5\text{ hours}}=\frac{1/0.5\text{ miles}}{0.5/0.5\text{ hours}}=\frac{2\text{ miles}}{1\text{ hour}}\)
That speed is 2 miles per hour.