We have a question on motion with the elements of distance, time taken and speed.
This question in particular is asking us for distance per unit time (in this case, hours).
We are required to find out how much distnace is covered in on hour and our approach will be as follows:
This right here just tells us that 4 hours, Madeline covered 180 miles and since her rate was constant (equal distances in equal times), then she also covered 45 miles in an hour.
Now we plot our number line.