SOLUTION: After taking 4 quizzes, your average is 76 out of 100. What must your average score be on the next five quizzes to increase your average to 81?

Question 215557: After taking 4 quizzes, your average is 76 out of 100. What must your average score be on the next five quizzes to increase your average to 81?
Answer by drj(1380) (Show Source): You can put this solution on YOUR website!
After taking 4 quizzes, your average is 76 out of 100. What must your average score be on the next five quizzes to increase your average to 81?

Step 1. Let x be the average of the next five quizzes.

Step 2. Let 4*76 be the 4 quizzes with each quiz having a score of 76 so the average of the four quizzes is 76.

Step 3. There will be a total of 9 quizzes.

Step 4. The average of nine quizzes is . Solve for x as follow

Multiply 9 to both sides of equation to get rid of denominator

Subtract 304 to both sides of equation to get 5x on the right side

Divide by 5 to both sides of equation to solve for x

Step 5. ANSWER: To get an overall average of 81, the next five quizzes must average 85.

I hope the above steps were helpful.

For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.

Good luck in your studies!

Respectfully,
Dr J
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