In a certain school, course grades range from 0 to 100. Adrianna took 4 courses and her mean course grade was 90. Roberto took 5 courses. If both students have the same sum of course grades, what was Roberto’s mean?
- A72
- B80
- C90
- D92
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Correct answer: A
The sum of Adrianna’s course grades equals 4 times the mean (average) of her grades:
90 × 4 = 360
Roberto has the same sum as Adrianna. Find the mean of his course grades:
360 ÷ 5 = 72