j_shreyans wrote:For a set X containing n integers, is the mean even?
(1) n is even.
(2) All of the integers in set X are even.
Target question: Is the mean even?
Statement 1: n is even.
This statement doesn't
FEEL sufficient, so I'm going to TEST some values.
There are several sets that satisfy statement 1. Here are two:
Case a: the numbers are {12, 12}. Here, n is even, and
the mean = 12, which is EVEN
Case b: the numbers are {10, 12}. Here, n is even, and
the mean = 11, which is ODD
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, you can read my article: https://www.gmatprepnow.com/articles/dat ... lug-values
Statement 2: All of the integers in set X are even.
This statement doesn't FEEL sufficient either, so I'm going to TEST some values.
There are several sets that satisfy statement 1. Here are two:
Case a: the numbers are {12, 12}. Here, all of the integers are even and
the mean = 12, which is EVEN
Case b: the numbers are {10, 12}. Here, all of the integers are even and
the mean = 11, which is ODD
Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
Combined, we still get the same two cases:
Case a: the numbers are {12, 12}. Here n is even AND all of the integers are even. In this case,
the mean = 12, which is EVEN
Case b: the numbers are {10, 12}. Here n is even AND all of the integers are even. In this case,
the mean = 11, which is ODD
Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer =
E
Cheers,
Brent
