1.- Determine the independent and dependent variable.
The independent variable is the variable in a problem that taker its own values
--> is independent of the value of the other variable.
And the dependent variable is the variable that depends on the independent variable.
In this case we have two variables: Number of cupcakes and frosting needed.
The independent variable is the number of cupcakes
The dependent variable is the frosting needed, because the frosting that is needed depends in the number of cupcakes. Thus it is the dependent variable.
2.- Explain the relationship between the two.
The relationship between number of cupcakes and frosting needed is a linear and proportional relationship. Because the number of cupcakes determines the amount of frosting needed:
if we have more cupcakes, we will need more frosting.
if we have less cupcakes, we will need less frosting.