Given the results of the two tests are 90% and 84%, we are interested to have a result in the third test such that the average of these three (3) tests will fall under the range of A. That is:
Let x be the result of the third test in percentage. So we have,
AVERAGE = (90% + 84% + x) / 3.
Since A lies within the range of 90% to 100%, we want the average to lie on this range. That is,
90% <= AVERAGE <= 100%.
Case 1: 90% <= AVERAGE
If the target grade is the lower bound of A, that is 90%, then we have the following:
90% <= (90% + 84% + x%) / 3
270% <= 90% + 84% + x
x <= 270% - 90% - 84%
x <= 96%.
Thus, you have to obtain a score of at least 96% to get a grade of A in the class.
Case 2: AVERAGE <= 100
If the target grade is the upper bound of A, that is 100%, then we have the following:
100% <= (90% + 84% + x%) / 3
300% <= 90% + 84% + x
x <= 300% - 90% - 84%
x <= 126%.
Thus, you have to obtain a score of at most 126% to get a grade of A in the class.
Combining these two results, we have 96% <= x <= 126%. That means, your score in the third test must ranged from 96% to 126% to obtain a grade of A in the class.
Note that in some instances that a student's grade in a test can exceed 100% whenever the student answered correctly the bonus item(s) (commonly a very tough item) given by the teacher (or professor) in a test.
2006-11-15 17:55:01
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answer #1
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answered by rei24 2
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at least 96.
at least a 90 is needed for an A. you already got 90 for the first one. You're 2nd one is 6 points short of getting an A. your last one has to be 90 + 6 to make up for the 2nd one. so 96.
Mathematically, it will look like this.
1. (90 + 84 + C) / 3 = 90
2. (174 + C) = 90 x 3
3. 174 + C = 270
4. C = 270 - 174
5. C = 96
2006-11-16 01:31:01
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answer #2
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answered by Anonymous
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Let X = third test grade
(90 + 84 +x) / 3 > 90%
solve for X:
90 + 84 + X > 270
X > 270 - 90 - 84
X > 96
meaning that you have to get at least a 96% on the third test!
2006-11-16 01:25:04
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answer #3
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answered by pink 5
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90 average means 270 total on 3 tests.
you have 90+84=174 so far.
You need 270-174=96 on the last test.
If this is for your math class, i think you have a problem.
2006-11-16 01:24:53
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answer #4
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answered by yupchagee 7
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90+84+96=270
270/3=90%
u need to get approximately 96% on ur last test in order to get an A.
good luck
2006-11-16 01:27:07
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answer #5
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answered by logan 2
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you already have one ninety so you need another on the next test plus 6 points to make up for the 84 you got on the other test.
if they are all weighted the same.
2006-11-16 01:54:03
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answer #6
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answered by dt 3
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u need a 96% to get at least a 90% (A)
2006-11-16 01:32:30
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answer #7
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answered by krazyfreak 3
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You need at least a 96
2006-11-16 01:30:36
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answer #8
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answered by konala 3
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At least 96.
2006-11-16 01:25:51
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answer #9
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answered by yezdi 2
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atleast 96....if all the three exams have same weightage..
2006-11-16 01:30:48
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answer #10
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answered by satyagrahi 2
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