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by [email protected] » Sat Aug 03, 2013 7:23 am
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Is X a positive integer?

(1) |x| >1

(2) 1<x<2


Should A be a correct choice? |X| means +-X is greater than one doesn't it mean the value of X is positive hence an integer?
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Source: — Data Sufficiency |

by Matt@VeritasPrep » Sat Aug 03, 2013 8:01 am
If I'm reading the inequalities correctly, we have

S1:: |x| > 1
S2:: 2 > x > 1

From S2, x isn't an integer - SUFFICIENT.

From S1, either x > 1 or -1 > x. NOT SUFFICIENT. (x could be -1.5, or 3.7, or whatever.)
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by [email protected] » Sat Aug 03, 2013 2:35 pm
Hi shibsriz,

To select the correct answer to a DS question, you have to pay attention to whether the answer to the question stays the same or changes. Take lots of notes and pay attention to the details, and these questions are usually straight-forward.

In this DS question, we're asked if X is a POSITIVE INTEGER? This is a yes/no question.

Fact 1 tells us |X| > 1

Let's TEST some values and track the results:
If X = 2, then the answer to the question is YES
If X = 1.5, then the answer to the question is NO
And just for the reference....
If X = -3, then the answer to the question is NO
The answer is inconsistent (it changes), so Fact 1 is INSUFFICIENT to answer the question.

Fact 2 tells us that 1 < x < 2
So X has to be a decimal between 1 and 2
X = 1.5 and the answer to the question is NO
X = 1.9999 and the answer to the question is NO
X = 1.1 and the answer to the question is NO
The answer is consistent (it stays the same), so Fact 2 is SUFFICIENT on its own.

Final Answer: B

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
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