Question 928781: An average score of at least 80, but less than 90, in a history class receives a B grade. Rebecca has scores of 86, 72, and 94 on three test. Find the range of scores she could receive on the fourth test that would give her a B grade for the course. Assume that the highest test score she can receive is 100.
Answer by TimothyLamb(4379)   (Show Source):
You can put this solution on YOUR website! lowest score on the fourth test for a B in the class:
(86 + 72 + 94 + x)/4 = 80
(86 + 72 + 94) + x = 80*4
x = 80*4 - (86 + 72 + 94)
x = 68
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highest score on the fourth test for a B in the class:
(86 + 72 + 94 + x)/4 = 89
(86 + 72 + 94) + x = 89*4
x = 89*4 - (86 + 72 + 94)
x = 104
cannot get 104 on the fourth test, because the maximum test score is 100
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answer:
range of scores on fourth test for a B in the class: 68 to 100
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