Answer:
The given problem is about the decrease of two variable, where [tex]x[/tex] represent years and [tex]y[/tex] represents video rental.
The ratio here refers to the slope of the linear decreasing behaviour, where pairs are (1996,9) and (2016, 4). The formula for the slope is
[tex]m=\frac{y_{2}-y_{1}}{x_{2}-x_{1} }=\frac{4-9}{2016-1996}=\frac{-5}{20}=-\frac{1}{4}\\ m=-0.25[/tex]
This means that the linear relation decreases, with a constant ratio of 0.25, that is, video rental decreases one per 4-years periods.
