SOLUTION: Jack had an average score of 85 on his first eight quizzes, and an average score of 81 on his first nine quizzes. What score did he receive on his ninth quiz?

Question 318497: Jack had an average score of 85 on his first eight quizzes, and an average score of 81 on his first nine quizzes. What score did he receive on his ninth quiz?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Jack had an average score of 85 on his first eight quizzes, and an average score of 81 on his first nine quizzes. What score did he receive on his ninth quiz?
-----
Points acquired on the 1st 8 quizzes = 8*85 = 680
---
Let "x" be the score on the ninth quizz.
------------
Equation:
Solve for "x":
(680+x)/9 = 81
680+x = 729
x = 49
================
Cheers,
Stan H.
RELATED QUESTIONS
On the first 6 quizzes of his math class, Luis got an average score of 78. What does he... (answered by richwmiller)

On the first 4 quizzes of his chemistry class, Brandon got an average score of 81.... (answered by ewatrrr)

On the first 3 quizzes of his geometry class, Christopher got an average score of 81.... (answered by ewatrrr)

On the first 5 quizzes of his physics class, Daniel got an average score of 85. What... (answered by Cromlix)

Jason has an average grade of 85 on his first 8 quizzes. After his 9th quiz, his average... (answered by Cromlix)

Alex received scores of 82 and 88 on his first two quizzes. What average score does he... (answered by Fombitz,CharlesG2)

Sean took 4 quizzes and has an average of 85%. He wants to raise his average to a 92%.... (answered by Boreal)

Jayden has scores of 9, 6, 10, 5, 6 and 8 on his first six quizzes. If he wants an... (answered by Fombitz)

Translate the following into an inequality. DO NOT SOLVE A student scored 89 and 72 on (answered by rfer,richard1234)