Answer:
84 or more on the third exam.
Step-by-step explanation:
Since we know the first two scores of the exam, which would be 75 + 81 = 156. We want to find an average that should equal 80 or more.
We get the following setup.
(75 + 81 + x) / 3 >= 80
We want to find the value of x that is the ideal score to get an average of 80 out of all the scores.
(156 + x) / 3 >= 80
156 + x >= 240
x = 84
