A student received the following scores in a Mathematics course: 72, 85, 91, 78, and 88 on five quizzes. She also scored 89 on the midterm exam, 93 on a group project, and 75 on assignments. The final grade is determined by the following weight distribution: Quizzes (50%), Midterm Exam (20%), Project (15%), and Assignments (15%). What is the student's weighted mean score? What letter grade did she earn (A, B, C, D, or F)? Assume that a mean of 90 or above is an A, a mean of 80 to 89 is a B, and so on.
