To question 16, we see that for every change of plus 2 drinks, they pay an additional value of $2.50. It means that each drink does cost half of this value.
This way, the equation that will give the value of the total cost will be:
[tex]Y=1.25\times X[/tex]
Where X stands for the number of drinks, and 1.25 is the value of a single drink.
From the solution presented above, we are able to conclude that the rate of change represents the value of a unitary drink, in the present situation.
