Express the distance (d) traveled as a function of the number of hours (h) at an average speed. The Morris family is traveling from Providence to Fredricksburg. Given city traffic, they will average 45 miles per hour.

I don't know what you're question is...
D/T = V
V of Morris= 45m/h

Okay, but what do you need to know?

What is average speed? It is the total distace covered divided by the total time.

d = distance, h = time (in hours)

Let speed = s, you can get your expression for distance, from s=d/h.

I suppose if you're given the time they take to go from Providence to Fredricksburg, find the distance between these two places by the expression you got earlier.