4quiz scores of 86 +91 +81 +86. what score would you need to average 85

If you are asking what score is needed on a 5th quiz to average 85:

x= 5th quiz score

(86 + 91 + 81 + 86 + x)/5= 85
add all in parentheses

(344 + x)/5= 85
multiply both sides by 5

344 + x= 425
subtract 344 from both sides

x= 81

ANSWER: An 81 is the minimum score needed on the 5th quiz to have an average of 85.

Hope this helps! :)

answer in pic, hope it helps