At a tutoring center, students are divided into three sessions: morning, afternoon, and evening. The average score on a practice test for the morning session is 85, for the afternoon session is 78, and for the evening session is 90. There are 3 times as many students in the morning session as in the evening session. There are half as many students in the afternoon session as in the morning session. What is the average practice test score for all students combined?
82
83
84
85
86
