SOLUTION: Rita earns scores of 78, 82, 90, 80, and 75 on her five chapter tests for a certain class and a grade of 85 on the class project. The overall average for the course is computed as

Question 1112783: Rita earns scores of 78, 82, 90, 80, and 75 on her five chapter tests for a certain class and a grade of 85 on the class project. The overall average for the course is computed as follows: the average of the five chapter tests makes up 60% of the course grade; the project accounts for 10% of the grade; and the final exam accounts for 30%. What scores can Rita earn on the final exam to earn a �B� in the course if the cut-off for a �B� is an overall score greater than or equal to 80, but less than 90? Assume that 100 is the highest score that can be earned on the final exam and that only whole-number scores are given.
Thank you for your help.
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The average of the exams is the sum divided by the number of them or 405/5=81
That is 0.6 of the grade so the actual number of the final grade is the product of 0.81 (81%) and 0.6. or 48.6%
The project's contribution is .85*0.1=0.085=8.5%
Going into the final, the score is 57.1%
To make an 80 the score* 0.30 must be 22.9. Therefore, the score is 22.9/0.30, or 76 1/3%
To make a 90, the score*0.30 must be 32.9, so the score needed is 32.9/0.3, or 109 2/3%
The score must be at least 77, to the lowest integer, to get a score of at least 80. Any higher will be acceptable, and 90 is not possible, even with a perfect score on the project.
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