Ms. Quarles gave the same math unit test to all her classes. She grades 25% of the tests, which is 30 papers. How many students does Ms. Quarles have in total
If 30 papers represent 25% of the total number of students, then the total number of students in all her classes is:
30 / 0.25 = 120 students
Therefore, Ms. Quarles has 120 students in total.