Melissa’s grade in her math class is determined by three 100-point tests and a 200-point final exam. To determine the grade for a student in this class, the instructor will add the four scores together and divide this sum by 5 to obtain a percentage. This percentage must be at least 80 for a grade of B. If Melissa’s three test scores are 75, 69, and 87, what is the minimum score she needs on the final exam to obtain a B grade?