Answer
14 sit-ups per day
Explanation
To solve this, we are going to use the slope formula:
[tex]m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]
where
[tex](x_{1},y_{1})[/tex] are the coordinates of the first point on the line
[tex](x_{2},y_{2})[/tex] are the coordinates of the second point
From our graph we can infer that Sereita did 14 sit-ups the first day, so our first pint is (1, 14); we can also infer that Sereita did 28 sit-ups the second day, so our second point is (2, 28). From our points we can infer that [tex]x_{1}=1[/tex], [tex]y_{1}=14[/tex], [tex]x_{2}=2[/tex], and [tex]y_{2}=28[/tex], so let's replace the values in our slope formula:
[tex]m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]
[tex]m=\frac{28-14}{2-1}[/tex]
[tex]m=\frac{14}{1}[/tex]
[tex]m=14[/tex]
Since the unit rate is the slope of our line, we can conclude that the unit rate is 14 sit-ups per day.
