The correct answer is:
The faster rate is when she hiked down 200 feet in 10 minutes.
Explanation:
The rate of change is given by the change in y over the change in x; in this case, the change in elevation over the change in time.
For the first part of the hike, the change in elevation was -200 and the change in time was 10; this gives us a rate of change of -200/10 = -20.
For the second part of the hike, the change in elevation was -300 and the change in time was 20; this gives us a rate of change of -300/20 = -15.
She hiked downhill faster during the first part of the hike, at 20 feet per minute.