mean

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by vipulgoyal » Wed May 22, 2013 12:14 am
In a certain test, how many of the 35 students in a certain class got a score less than 85?
1). The average score of all students is 85
2). The median score of all students is 85
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by vipulgoyal » Wed May 22, 2013 12:17 am
my take B (17)

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by Atekihcan » Wed May 22, 2013 12:24 am
Consider the following scenarios for the scores of 35 students...
  • One student scored 84, 33 students scored 85, and one student scored 86
    Two students scored 84, 31 students scored 85, and two students scored 86
In both the above cases, average as well as median score of the students is 85.
But in the first case 1 student scored less than 85 and in the second case 2 students scored less than 85.

Answer : E

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by GMATGuruNY » Wed May 22, 2013 2:58 am
vipulgoyal wrote:In a certain test, how many of the 35 students in a certain class got a score less than 85?
1). The average score of all students is 85
2). The median score of all students is 85
When the statements are combined, there are only two constraints:
Sum = number*average = 35*85.
Median = 85.

The scores could all be the same:
85, 85, 85...85, 85, 85...85, 85, 85.
Here, there are no scores below 85.

The scores could look like this:
84, 85, 85...85, 85, 85...85, 85, 86.
Here, there is one score below 85.

The scores could look like this:
84, 84, 84...84, 85, 86...86, 86, 86.
Here, there are 17 scores below 85.

Thus, the two statements combined are INSUFFICIENT.

The correct answer is E.
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