Use the formula d = rt to figure this out, where d is distance, r is the rate of travel, and t is the total amount of time taken to travel the distance, d.
So the equation would be 350 = 5.15r (I converted 5 1/4 to a decimal to make it easier.) Now we simply need to solve for the variable r to get the final answer.
Once the equation is solved for r, the final answer is ABOUT 68 mph. So, Caroline drove at an average speed of 68 miles per hour.
