Question

graph below.
number of gallons used
distance traveled (miles)
(a) how many gallons does the train use per mile?
$\boldsymbol{square}$ gallon(s)
(b) what is the slope of the graph?
$\boldsymbol{square}$

Explanation:

Step1: Pick point from graph

Choose point $(x,y)=(100, 600)$ where $x$ is miles, $y$ is gallons.

Step2: Calculate gallons per mile

Divide gallons by miles: $\frac{y}{x} = \frac{600}{100}$

Step3: Simplify for part (a)

$\frac{600}{100}=6$

Step4: Find slope for part (b)

Slope = $\frac{\text{Change in } y}{\text{Change in } x} = \frac{600-0}{100-0}$

Step5: Simplify slope

$\frac{600}{100}=6$

Answer:

(a) 6 gallon(s)
(b) 6