didieravoaka wrote:What was the highest final exam grade in the class?
(1) The average (arithmetic mean) final exam grade was 75.
(2) The lowest final exam grade was 60.
Statement 1:
The mean is just the average of all the grades. By knowing that the mean is 75 we know that the highest grade must be at least 75, but we don't know whether the highest grade is greater than 75.
Insufficient.
Statement 2:
This alone tells us nothing about the highest grade.
Statements Combined:
Combined the statements seem to provide insight into the highest grade, and if the lowest is 60 and the mean is 75, then we do know that the highest grade must be greater than 75.
However, while one's initial inclination may be to say that combined the two statements are sufficient, the truth is that the highest grade could be any number greater than 75 because we don't know the number or distribution of the scores.
For instance, if there are just two scores, then given that the lowest score is 60, in order to create a mean of 75, the highest score must be 90.
If there are more than two scores - there could for instance be three scores, two of which are 60 - then the highest is different from what it would be were there only two.
Insufficient.
The correct answer is
E.
