Question

Your original grades on your exams were: 75, 85, 90, 90, 100, 75, 80, 100, 90. You retake the exams and now your scores are: 85, 85, 100, 90, 100, 85, 80, 100, 90. By how many percentage points did you improve your average score?​

Answer 1

Your average improved by 13
`(1)/(3)` %.

Explanation:

First set:

(75 + 85 + 90 + 90 + 100 + 75 + 80 + 100 + 90) ÷ 9 = 77
`(2)/(9\\)` %

Second set:

(85 + 85 + 100 + 90 + 100 + 85 + 80 + 100 + 90) ÷ 9 = 90
`(5)/(9)` %

Improvement:

90
`(5)/(9)` % - 77
`(2)/(9\\)` % = 13
`(1)/(3)` %