Your current test average in science is an 81. you’ve taken 5 tests. you only have one test remaining (there is not extra credit on your test). you can raise your average to an 85.

If you want to know what grade is needed to raise your average to an 85, add all tests, then divide by total number of tests to equal average of 85. The x value is the grade needed on the final to raise the overall class grade to an 85.

x= final test

(81 + 81 + 81 + 81 + 81 + x)/6= 85
add in parentheses

(405 + x)/6= 85
multiply both sides by 6

405 + x= 510
subtract 405 from both sides

x= 105 grade needed

ANSWER: Since there is no extra credit, it is impossible to raise the overall average to an 85 because they would need a final test grade of 105.

Hope this helps! :)