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Thread: tricky !

  1. #1
    Eager!
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    tricky !

    A number, x is chosen at random from the set of positive integers less than 10. What is the probability that (9/x) > x?

    (A) 1/5

    (B) 2/9

    (C) 1/3

    (D) 2/3

    (E) 7/9


    SPOILER: Actual Answer : B

  2. #2
    TOEFL : GRE :: Dimas's Avatar
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    9/x > x resolves to:
    9 > x^2 ===> -3 < x < 3
    As long as 0<x<10

    we have x={1,2} note that zero is neither positive nor negative.
    probability = 2/9 = {1,2} / {1,2,3,4,5,6,7,8,9}

  3. #3
    Everything is Karma karmaholic's Avatar
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    9/x > x will only hold for x = 1 and x = 2. (2 cases)

    total possible cases = 9.

    Required probability = 2/9.
    ॐ हौं जुं स: मृत्युंजयाय नम:॥ Salvation ..



  4. #4
    Within my grasp! Amorous's Avatar
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    x^2 < 9 is true for x=1 and x=2 out of 9 possibilities...

    -Amor

  5. #5
    Within my grasp! heike2504's Avatar
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    Sorry, but could someone please try to explain again? I can't see how you come to 9 > x^2 and what does ^ mean?

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