Answer:
-3.5
The distance Rachel covers per hour is 3.5 miles
Step-by-step explanation:
After 2 hours, she is 13 miles from the campground.
After 4 hours, she is 6 miles from the campground.
Let x be the number of hours, y be the number of miles from the campground, then we have two points (2,13) and (4,6).
The equation of the line passing through the points [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex] is
[tex]y-y_1=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]
Substitute:
[tex]x_1=2\\ \\y_1=13\\ \\x_2=4\\ \\y_2=6[/tex]
Hence,
[tex]y-13=\dfrac{6-13}{4-2}(x-2)\\ \\y-13=-3.5(x-2)\\ \\y=-3.5x+7+13\\ \\y=-3.5x+20[/tex]
The slope of the line is [tex]-3.5[/tex] and it represents that the distance Rachel covers per hour is 3.5 miles.
