GMAT Number Theory (Data Sufficiency)

Euclid · **Joined:** Sun Apr 19, 2009 7:25 pm **Posts:** 5

Is the positive integer P a prime number?
(1) 67 > P > 61
(2) is even.

with all the respect i have little doubt in my mind regarding your 2nd option. 2nd option says that P is even. Now as we know that 2 is the only prime number that is even , thus it provides us a clear evidence that the integer P is not a prime number as 2 is not localized between 61 and 67. So my point is that statement 2nd also gives us decisive indication that P is not a prime number. Please elaborate it a bit.

GMATguru · **Joined:** Mon Apr 06, 2009 5:44 pm **Posts:** 81

The second statement is not sufficient. It works sometimes and it fails other times. For example if P is equal to 2, then it is in fact a prime number, otherwise its not. There is no indication in the statement of the problem that P is even or odd.

questioner · **Joined:** Tue Apr 13, 2010 8:48 am **Posts:** 449

Sorry, but the question CLEARLY STATES that P is between 61 and 67… so how come 2 CAN be between 61 and 67? Unless I come from a different universe, P will ALWAYS be less than 61 and 67, therefore, making the 2nd. clause ALSO correct…

Maybe I'm misreading something, but I read it like a million times and can't find the error in my line of thought.
Regads

800score · **Joined:** Thu Jul 05, 2012 11:55 am **Posts:** 63

Quote:

Sorry, but the question CLEARLY STATES that P is between 61 and 67

Statement (1) tells so.

Quote:

so how come 2 CAN be between 61 and 67?

2 is NOT between 61 an 67. However it can be a value of P if we consider Statement (2) by itself. When we consider Statement (2) by itself we disregard information in Statement (1) as if it does NOT exist.

GMAT Number Theory (Data Sufficiency)

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