What range of grades for your 10th problem set will raise your overall average?

0 to 90

70 to 99

89 to 100

0 to 87

b. What range will lower your overall average?

70 to 99

0 to 87

89 to 100

0 to 90

c. In other words, if your grade on your 10th problem setyour "marginal" gradeexceeds your average grade, your average grade will

. If your "marginal" grade falls short of your average grade, your average grade will

.