Question 1070280
in order to score an average of 90 on 9 quizzes, she has to have a total score of 90 * 9 = 810.


she has a total of 8 * 89 = 712 on 8 quizzes.


810 - 712 = 98.


she needs to score a 98 on the 9th test in order to get an overall average of 90 on all 9 tests.