A freight train is carrying goods across the country. The distance it has traveled varies directly with the number of gallons of fuel it has used. See the graph below.

Answer:
Step-by-step explanation:
The train uses
[tex]\frac{400gallons}{200miles}[/tex]
If you reduce that you get that the train uses
[tex]\frac{2gallons}{1mile}[/tex]
To find the slope of the line, we will use the 2 points on the coordinate plane where the graph goes through: (0, 0) and (400, 200)
Applying the slope formula:
[tex]m=\frac{200-0}{400-0}=\frac{1}{2}[/tex]