Data Sufficiency

candygal79 wrote:If x is a positive number, is x < 16 ?
1) x is less than average of the first ten positive integer
2) x is the square of an integer

Target question: Is x < 16

Statement 1: x is less than average of the first ten positive integer
The first 10 positive integers are 1,2,3,4,5,6,7,8,9,10
Since NONE of these values is greater than 16, we can be certain that their average is less than 16.
Since we're told that x is LESS THAN the average, we can conclude that x is definitely less than 16.
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x is the square of an integer
There are several values of x that satisfy this condition. Here are two:
Case a: x = 9 (i.e., 3²), in which case is less than 16
Case b: x = 25 (i.e., 5²), in which case is NOT less than 16
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer = A

Cheers,
Brent