Question 513059: manuel has scores of 77 82 89 89 and 92 on 5 class exams. his final exam is going to count double. what score must he get on the final exam so that his total average is at least 87?
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! Manuel will take a total of 7 exams ... the 5 that he already has taken plus the 1 exam that will count as 2 tests since it counts double.
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If Manuel is to average 87 for 7 exams, he needs to score a total of 609 points (87 * 7 = 609 points so that 609 points divided by 7 = 87, the average he wants).
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On the 5 exams he has already scored 77+82+89+89+92 = 429 points. That means that he still has 609 minus 429 points to go. Subtracting 429 from 609 tells you that he has 180 points that he must score. Since the final test counts for 2 exams, if he scores a 90 on it, that score will double to give him the 180 points he needs to ensure his average is 87. If he scores more than 90 points, his average will be greater than 87.
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Hope this helps you to understand this problem.
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