SOLUTION: Yasi is trying to get a B in her english class. To earn a B in the course, she must average a score of 80 on the 15 quizzes. She has taken 12 quizzes and averaged 78.25 points on

Question 668684: Yasi is trying to get a B in her english class. To earn a B in the course, she must average a score of 80 on the 15 quizzes. She has taken 12 quizzes and averaged 78.25 points on them. How many points does Yasi need to average on the last 3 quizzess to earn a B in the course.
Found 3 solutions by stanbon, amazingrace333, lynnlo:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
Yasi is trying to get a B in her english class. To earn a B in the course, she must average a score of 80 on the 15 quizzes. She has taken 12 quizzes and averaged 78.25 points on them. How many points does Yasi need to average on the last 3 quizzess to earn a B in the course.
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On 12 quizzes she has a sum of 12*78.25 = 939 points.
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To average 80 on 15 quizzes she needs 15*80 = 1200 point.
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She needs 1200-939 = 261 points in 3 tests
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She needs to average 261/3 = 87 on the three tests.
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Cheers,
Stan H.
Answer by amazingrace333(11)   (Show Source): You can put this solution on YOUR website!
To get a B or an average of 80 on 15 quizzes, the sum total of your scores must equal to 80 x 15 or 1200 points total.
If your average is 78.25 on 12 quizzes, you need to find out how many points out of the 1200 total that you still need. To do this, you multiply 78.25 x 12 to get the total points you have so far. 78.25 x 12 = 939
Now to find out how many points you need on the final 3 quizzes, subtract 939 from the original 1200 points needed. 1200-939 = 261
Since you are looking for the average grade you need on the final 3 quizzes, divide 261 by 3 to get the final average grade you need on the last 3 quizzes or 87.
1200/15 = 80
939+261 = 1200
939/12 = 78.25
261/3 = 87

Answer by lynnlo(4176)   (Show Source): You can put this solution on YOUR website!
85
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