- #1
Holocene
- 237
- 0
Homework Statement
The grade in a class is determined by three tests and a final exam. The final exam counts twice as much as a test. A student's three test grades are 78, 82, and 100. What does he need to score on the final exam to bring his average up to 90?
Homework Equations
Please check this work; book is not giving this answer as a solution.
The Attempt at a Solution
[tex]\displaystyle{\frac{78 + 82 + 100 + 2x}{4} = 90}[/tex]
[tex]\displaystyle{\frac{260 + 2x}{4} = 90}[/tex]
[tex]\displaystyle{260 + 2x = 360}[/tex]
[tex]\displaystyle{2x = 100}[/tex]
[tex]\displaystyle{x = 50}[/tex]
The student needs a score of 50 on the final exam to yeild an overall average of 90.