Final answer:
In the fitness class payment scenario, the independent variable is the number of classes taken, and the dependent variable is the total cost, which includes the $10 cost per class and a $15 registration fee.
Step-by-step explanation:
In the situation described where fitness classes cost $10 per class and have a registration fee of $15, the independent variable is the number of classes a student takes. This is because the independent variable is the one that you change or control to see how it affects the dependent variable.
In this case, the more classes you take, the higher your total cost will be. The dependent variable is the total cost for the classes. This cost depends on how many classes are taken, hence why it is considered 'dependent'.
To express this with an example, if a student decides to take 5 classes, the independent variable would be 5 (classes), and the dependent variable would be the total cost, which is calculated by multiplying the number of classes by the cost per class and adding the registration fee: 5 classes * $10/class + $15 = $65 in total.