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Math Help - GRE Question

  1. #1
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    GRE Question

    If 0 < st < 1, then which of the following can be true?

    a.) s < -1 and t > 0

    b.) s < -1 and t < -1

    c.) s > -1 and t < -1

    d.) s > 1 and t < -1

    e.) s > 1 and t > 1

    The answer is c.)... how?

    If s > -1, that means s = 0, 1, 2, ...

    If t < -1, that means t = -2, -3, ...
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  2. #2
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    Quote Originally Posted by Ideasman View Post
    If 0 < st < 1, then which of the following can be true?

    a.) s < -1 and t > 0

    b.) s < -1 and t < -1

    c.) s > -1 and t < -1

    d.) s > 1 and t < -1

    e.) s > 1 and t > 1

    The answer is c.)... how?

    If s > -1, that means s = 0, 1, 2, ...

    If t < -1, that means t = -2, -3, ...
    first note the wording of the question.

    no way any of the other choices will work, no matter what numbers you pick for s and t that meet the given restrictions.

    don't limit yourself to integer values.

    for (c) ... let s = -1/5 and t = -2
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  3. #3
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    They should specify that it's all reals then and not just integers!

    Thanks.
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  4. #4
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    Quote Originally Posted by Ideasman View Post
    They should specify that it's all reals then and not just integers!

    Thanks.
    where does the question state that only integral values should be used?
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  5. #5
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    His point appears to be that "numbers" automatically means integers. After all, he is taking the GRE so he has only had 12 years of school and 4 years of college. You can't expect him to have worked with fractions or irrational numbers in that little time!

    Frankly, I'm surprised he didn't complain that they didn't specifically tell him that the test is in English! Otherwise how can he be sure what "of" and "the" mean?
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