The principal and two counselors are 3 people in total.
There will be 85 - 3 = 82 maximum seats left for the juniors and their parents.
Let 'x' represent the number of students, and we assume that each student brings only one parent. This means there will be x parents at the conference.
Now we can write:
x + x = 82
x = 31 students
31 students can attend each meeting.