Question

Alice's average mark for 4 Science exams is 68%. Can Alice score enough marks in a fifth exam so that her average mark increases to 75?%? Give reasons.

Answer 1

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%