Answer:
It is not possible for Alice to score an average of 75% because what she needs to score in the fifth exam exceeds the maximum possible score.
Step-by-step explanation:
She scored an average 68% in all 4 exams.
This means; (68% + 68% + 68% + 68%)/4
Now, a fifth exam is added and we want to know if her average can now be 75%.
Thus, let the score in the 5th exam be x and we now have;
(68% + 68% + 68% + 68% + x)/5 = 75%
Multiply both sides by 5 to get;
(68% + 68% + 68% + 68% + x) = 375%
272% + x = 375%
x = 375% - 272%
x = 103%
The maximum score is 100% and therefore it is impossible for her to score 103%. Therefore it is not possible for Alice to score an average of 75%
