Write a compound inequality for the graph shown.
Rachel hikes at a steady rate from a ranger station to a campground that is 20 mi away. After 2 h, she is 13 mi from the campground. After 4 h, she is 6 mi from the campground. A graph shows her distance from the campground y, in miles, after x hours. What is the slope of the graph, and what does it represent?