Answer:
A score of 89
Explanation:
To find the average, we'll need to add all the results and divide them by the number of her exams. To do this, we'll need to add all her scores and one more (her next score to make the average 85): we'll call that x for now.
(80 + 82 + 83 + 91 + x) รท 5 = 85
(336 + x)/5 = 85
Multiply 5 on both sides
336 + x = 425
x = 89
Therefore, Monica will need an 89 on her next test for her average to be 85.
I hope this helped. Good luck and keep studying!