Tiffany's goal is to earn a semester average of 90 in her biology class. her teacher uses the following equation to determine semester averages, where a is the semester average, f is the first nine weeks’ grade, s is the second nine weeks’ grade, and e is the final exam score. a=3(f+s)+e/7 Tiffany made an 88 for the first nine weeks and a 91 for the second nine weeks. What is the minimum score she needs on the final exam to have a semester average of 90? 91
95
93
89