Answer :
C. $4/1Gal
Explanation
Step 1
we have the graph of a line, where
y-axis represents the cost ( in dollars)
x-axis represents the Volume ( gallons)
hence, to find the unit price we need to find the slope of the line:
a)when you know 2 points from a lines, P1 and P2, you can find the slope by using this formula:
[tex]\begin{gathered} \text{slope}=\frac{change\text{ in y }}{\text{change in x}} \\ \text{slope}=\frac{y_2-y_1}{x_2-x_1} \\ \text{where} \\ P1(x_1,y_1) \\ P2(x_2,y_2) \end{gathered}[/tex]then, we need to pick up 2 points from the line
Let
P1(0,0)
P2(5,20)
Now, replace in the formula.
[tex]\begin{gathered} \text{slope}=\frac{y_2-y_1}{x_2-x_1} \\ \text{slope}=\frac{20dollars-0}{5gallons-0}=4\text{ }\frac{dollars}{\text{gallon}} \end{gathered}[/tex]therefore, the answer is
[tex]c)\text{ }4\text{ }\frac{dollars}{\text{gallon}}=\frac{4\text{ dollars}}{1\text{ gallon}}[/tex]I hope this helps you