First, we find the constant of proportionality
[tex]k=\frac{y_2-y_1_{}}{x_2-x_1}[/tex]Let's replace the points (8,12) and (10,15).
[tex]k=\frac{15-12}{10-8}=\frac{3}{2}=1.5[/tex]This means that 1 star is equivalent to 1.5 total points.
So, observe that 2 stars get 3 total points. 16 stars get 24 points. And, 12 stars get 18 points.