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Is x=1?

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ronnie1985 GMAT Destroyer!
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Is x=1? Post Sat May 19, 2012 11:20 pm
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  • Lap #[LAPCOUNT] ([LAPTIME])
    In this question , we get from statement 1 that x is 1 and from statement 2 that x is definitely not 1

    Then what should be the answer? (A) or (D)


    Is x=1?

    S1. (3x+2)+(3x-2) = 6

    S2. x^2-2x-3 = 0

    Please help???

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    Post Sun May 20, 2012 4:41 am
    Is x=1?

    Quote:
    S1. (3x+2)+(3x-2) = 6
    6x = 6
    x = 1
    Statement 1 is sufficient to answer the question.
    Quote:
    S2. x^2-2x-3 = 0
    (x+1)(x-3) = 0
    x = -1 or 3
    So we know that the value of x isn't 1. Statement 2 is sufficient to answer the question.

    The answer should be D. However, this question doesn't look like a GMAT type question. In a genuine GMAT type question, the answer to the question(If the answer is D) should be the same with both the statements. i.e If Statement 1 says 'YES', Statement 2 should also say 'YES' and not 'NO'. If it does so, one must question the source of the question.

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    Post Sun May 20, 2012 10:27 pm
    ronnie1985 wrote:
    In this question , we get from statement 1 that x is 1 and from statement 2 that x is definitely not 1

    Then what should be the answer? (A) or (D)


    Is x=1?

    S1. (3x+2)+(3x-2) = 6

    S2. x^2-2x-3 = 0

    Please help???
    Question is: Is x = 1?

    (1) (3x + 2) + (3x - 2) = 6
    6x = 6
    x = 1; SUFFICIENT.

    (2) x² - 2x - 3 = 0
    x² - 3x + x - 3 = 0
    x(x - 3) + 1(x - 3) = 0
    x = -1, 3, which clearly implies that x is not 1; SUFFICIENT.

    The correct answer is D. But the value of x is different from both the statements, which is not the case in a good GMAT question. The value of x should come out the same from both the statements. SO, I would not rate this as a good GMAT question.

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