To determine the number of classes members need to take so that the total monthly cost is the same as the total monthly cost for non-members, we need to set up an equation.
Let's use the variable "x" to represent the number of classes taken.
For members, the total cost is given by:
$50 (membership fee) + $5 (additional fee per class) * x (number of classes taken)
For non-members, the total cost is given by:
$10 (fee per class) * x (number of classes taken)
Setting up the equation, we have:
$50 + $5x = $10x
Simplifying the equation:
$50 = $5x
Dividing both sides of the equation by $5:
10 = x
Therefore, members need to take 10 classes in order to have the same total monthly cost as non-members.
The correct answer is C. 10.