SOLUTION: Jeff�s algebra test average will be an 88 if he gets a 72 on the next exam and a 91 if he gets a 90 on the next exam. If all exams are weighted the same, how many exams has Jeff ta

Question 1128136: Jeff�s algebra test average will be an 88 if he gets a 72 on the next exam and a 91 if he gets a 90 on the next exam. If all exams are weighted the same, how many exams has Jeff taken so far?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Jeff�s algebra test average will be an 88 if he gets a 72 on the next exam and a 91 if he gets a 90 on the next exam. If all exams are weighted the same, how many exams has Jeff taken so far?
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Let # of tests taken so far be "n".
Let the avg. score on those n tests be "k"
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Total of the scores on the first n tests = kn
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Equations::
(72+kn)/(n+1) = 88
(90+kn)/(n+1) = 91
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90+kn = 91(n+1)
72+kn = 88(n+1)
Subtract to get::
18 = 3(n-1)
3n = 21
n = 7 (# of tests taken so far)
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Cheers,
Stan H.
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