It took ivan 7.5 hours to drive 412.5 miles. how fast was he driving?

Since the question is asking how fast he is driving, we need to find his speed in miles per hour. To do this, you need to divide the amount of miles he drove by the amount of hours it took. When you do 412.5/7.5, you get the answer of 55 miles per hour. 

The answer would be choice b