Answer:
C. $1.25
Step-by-step explanation:
We have been given a graph that shows the cost of pens based on the number of pens in a pack. We are asked to find cost of one pen.
The cost of one pen would be equal to slope of line that connects the given points.
First of all, we will find slope of our given line using points [tex](3,3.75)[/tex] and [tex](9,11.25)[/tex] in slope formula.
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex], where,
[tex]y_2-y_1[/tex] = Difference between two y-coordinates,
[tex]x_2-x_1[/tex] = Difference between two x-coordinates of same y-coordinates.
Upon substituting our given values in slope formula, we will get:
[tex]m=\frac{11.25-3.75}{9-3}[/tex]
[tex]m=\frac{7.5}{6}[/tex]
[tex]m=1.25[/tex]
Therefore, the cost of one pen is $1.25 and option C is the correct choice.
