SOLUTION: Mariana averaged 76 on her first three exams. The first score was 77. The second score was 3 less than the third score. What did she score on the second and third exams?

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Question 1139272: Mariana averaged 76 on her first three exams. The first score was 77. The second score was 3 less than the third score. What did she score on the second and third exams?
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617)   (Show Source): You can put this solution on YOUR website!
SCORE 1       77
SCORE 2        c-3
SCORE 3        c
AVERAGE        76



SOLVE FOR c.
Answer by greenestamps(13198)   (Show Source): You can put this solution on YOUR website!


Since the problem involves the average of three numbers that are close together, challenge yourself to solve the problem by logical reasoning with some simple arithmetic. It's excellent brain exercise.

(1) The first score was 1 over the average.
(2) Therefore the second and third scores must combine to be 1 under the average.
(3) If two scores together are 1 under the average and those two scores differ by 3, then the scores are 1 over the average and 2 under the average.

ANSWER: 2nd test score 2 under the average = 74; 3rd test score 1 over the average = 77.
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