Final answer:
The equation that expresses the total cost in terms of the number of students in a class is: Total cost = $50 x number of classes + $20 x number of students. This equation takes into account the fee of $50 per class and $20 per student. Therefore, the most appropriate option is C.
Step-by-step explanation:
The equation that expresses the total cost in terms of the number of students in a class is:
Total cost = $50 x number of classes + $20 x number of students
This equation takes into account the fee of $50 per class and $20 per student. By multiplying the number of classes by the fee per class and the number of students by the fee per student, you can find the total cost Emma pays.