Answer
approximately $217$ miles per hour
Work Step by Step
Given, relevant information: 500 miles were traveled in 3.2 hours.
The formula for distance is $d=rt$, and it can be expressed in terms of $r$ (which is desirable because that variable represents the speed of the moving object, and the equation will give the answer directly if the $r$ is isolated on one side of the equation) like this:
$r=\frac{d}{t}$
The variables $d$ and $t$ are given, and plugging them into the above equation for speed results in the following:
$r=\frac{500}{2.3}$
$500\div2.3\approx217.391304348$
Since the distance was given in miles and the time spent traveling was given in hours, the answer provided by the speed equation will automatically be in MPH, so that is how the answer should be given. Also, it should be rounded to 3 significant figures, because no other directive is given by the textbook.
Final Answer: Approximately $217$ miles per hour