Answer:
4 mph
Explanation:
Select the steepest line. To choose this see how far she goes in a certain amount of time. We know that she takes one hour to go three miles, and takes a break. Then, we see that she went 2 miles in half an hour. If we mulitply this by 2, we get 4 miles per hour. The other line is 2 miles per hour, so her fastest speed is 4 mph.