Class 61 has a student. If class 1 is transferred to class 2, the number of students in the two classes is equal. Class 62 has () students?

Class 61 has a student. If class 1 is transferred to class 2, the number of students in the two classes is equal. Class 62 has () students?

Let B be X
Then A-B = x + B
So a-2b