SOLUTION: Erika’s teacher summarized the achievement test results of her class in the table below. Erika’s score is 79 and claims that she belongs to the upper 20% of her class. Prove th

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Question 1193724: Erika’s teacher summarized the achievement test results of her class in the table below. Erika’s score is 79 and claims that she belongs to the upper 20% of her class. Prove that her claim is correct.
Score f
90-99 3
80-89 4
70-79 6
60-69 11
50-59 8
40-49 5
30-39 3


Answer by Solver92311(821)   (Show Source): You can put this solution on YOUR website!


With only the data provided, she cannot prove that she is in the top 20% of the class. In order to be in the top 20% of the class, she would have to be one of the top eight out of the 40 students -- . This is only possible if she was the ONLY student in the 70-79 range who scored 79. If only one other student in that range scored 79 also, then she could only prove that she was in the top 22.5% of the class. The data does not specify how many of the six students in the 70-79 range scored 79; it could have been all six. Her only other option to prove the top 20% claim would be to somehow demonstrate that she was superior in some way to any other student who scored exactly 79.


John

My calculator said it, I believe it, that settles it

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