Is 1 Prime Number??

Hi,
Till date I was under the impression that 1 is neither prime nor composite.
But the explanations given by OG11 for question 118 is considering 1 as prime. Please let me know whether to consider 1 as prime or not while solving DS.

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Re: Is 1 Prime Number??

by dumb.doofus » Mon May 04, 2009 12:04 pm

rahul26 wrote:Hi,
Till date I was under the impression that 1 is neither prime nor composite.
But the explanations given by OG11 for question 118 is considering 1 as prime. Please let me know whether to consider 1 as prime or not while solving DS.

You got eyes of a hawk man!!

Very well observed.. I agree with you.. that's a mistake in OG.

1 is not a prime number.

One love, one blood, one life. You got to do what you should.
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Ian Stewart: GMAT Instructor; Posts: 2621; Joined: Mon Jun 02, 2008 3:17 am; Location: Montreal; Thanked: 1090 times; Followed by:355 members; GMAT Score:780

by Ian Stewart » Mon May 04, 2009 12:08 pm

That's Q118 in the DS section of OG11, and yes, it's a mistake. 1 is definitely not a prime number. I pointed out that error and two others in OG11 here:

https://gmatix.com/blogging/index.php?x=30

For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

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