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If r is represented ....

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factor26 Rising GMAT Star Default Avatar
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If r is represented .... Post Mon Nov 28, 2011 3:24 pm
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  • Lap #[LAPCOUNT] ([LAPTIME])
    If r is represented by the decimal 0.t5 what is the digit t ?

    1) r < 1/3
    2) r < 1/10

    i researched this question on the btg site but it doesnt look like a lot of people answered it ... PLEASE HELP

    OG answer is b

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    kanwar86 Rising GMAT Star
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    Post Mon Nov 28, 2011 3:38 pm
    factor26 wrote:
    If r is represented by the decimal 0.t5 what is the digit t ?

    1) r < 1/3
    2) r < 1/10

    i researched this question on the btg site but it doesnt look like a lot of people answered it ... PLEASE HELP

    OG answer is b
    Option 1, r<1/3 or r<0.33 (aprox)
    As r= 0.t5; Here t can be 0,1 or 2. All of them are less than 0.33 (No unique solution)
    Hence, 1) is not sufficient.
    Option 2, r<0.1
    Now, only t=0 satisfies 0.05<0.1
    Hence, option 2 is sufficient. Answer is B)

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    pemdas GMAT Titan Default Avatar
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    Post Mon Nov 28, 2011 6:49 pm
    r=0.t5
    st(1) r<1/3 OR 0.t5<1/3, 3*0.t5<1 which is equivalent to 0.(t+1)5<1. It's clear that t can be {0,1,2,3,4,...} Not Sufficient
    st(2) r<1/10 by applying the same logic as in st(1) we get 10*0.t5<1 and t.5<1 which is only possible for t=0 Sufficient

    ans is B

    factor26 wrote:
    If r is represented by the decimal 0.t5 what is the digit t ?

    1) r < 1/3
    2) r < 1/10

    i researched this question on the btg site but it doesnt look like a lot of people answered it ... PLEASE HELP

    OG answer is b

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    Anurag@Gurome GMAT Instructor
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    Post Mon Nov 28, 2011 9:59 pm
    factor26 wrote:
    If r is represented by the decimal 0.t5 what is the digit t ?

    1) r < 1/3
    2) r < 1/10

    i researched this question on the btg site but it doesnt look like a lot of people answered it ... PLEASE HELP

    OG answer is b
    (1) r < 1/3 implies r can be 0.25, 0.15, or 0.05. Since we do not get a definite answer, so (1) is NOT sufficient.

    (2) r < 1/10 or r < 0.10 implies r can be 0.05, so the only possibility for digit t is 0; SUFFICIENT.

    The correct answer is B.

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    factor26 Rising GMAT Star Default Avatar
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    Post Sat Dec 03, 2011 4:49 pm
    @ANURAG ... EXCELLENT EXPLINATION ... SHORT AND TO THE POINT ... MANY THANKS!

    mzalmati Just gettin' started! Default Avatar
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    Post Fri Feb 24, 2012 9:09 am
    I think the correct answer should be "E". Because you are not restricted to positive values. So, even the 2nd statement is insufficient.
    For instance: if r =0.05, then t=0
    if r = -0.15, then t = 1 and so on.
    It should be mentioned that the decimal number is positive, in that case the right answer would be "B"

    shawndx Just gettin' started! Default Avatar
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    Post Fri Mar 23, 2012 6:44 am
    Quote:
    I think the correct answer should be "E". Because you are not restricted to positive values. So, even the 2nd statement is insufficient.
    For instance: if r =0.05, then t=0
    if r = -0.15, then t = 1 and so on.
    It should be mentioned that the decimal number is positive, in that case the right answer would be "B"
    I also thought the same initially, but upon further inspection the question stem indirectly tells you that you are restricted to positive values since R=0.t5 and therefore it is not possible for R=-0.t5

    with that logic if r is less than 0.1 and it has to have a 5 in the 100th's digit the only possible value for r would then be 0.05---> t is equal to 0 and so B is sufficient

    snigdhakul Just gettin' started! Default Avatar
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    Post Tue Apr 10, 2012 3:40 am
    Quote:
    I also thought the same initially, but upon further inspection the question stem indirectly tells you that you are restricted to positive values since R=0.t5 and therefore it is not possible for R=-0.t5

    with that logic if r is less than 0.1 and it has to have a 5 in the 100th's digit the only possible value for r would then be 0.05---> t is equal to 0 and so B is sufficient
    Can we be sure that in GMAT if the question is given in the form of R=0.abc then we should restrict ourselves to only positive value and not assume the negative values?

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