SET 24 Math Q: 26:

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SET 24 Math Q: 26:

by neeraj_99 » Sun Oct 28, 2007 9:49 pm
26
Does the decimal equivalent of P/Q, where P and Q are positive integers, contain only
a finite number of nonzero digits?
(1) P>Q
(2) Q=8

pl. explain, too....IMO B, but OA is......., will tell later...i'm confused...
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by camitava » Sun Oct 28, 2007 10:42 pm
neeraj_99,
To me, as the question is saying about decimal equivalent of P/Q so the answer will always be integer. Now if P < Q, then there is a probability that decimal equ. of P/Q = 0. But the Qs is looking for finite number of non-zero elements. So to me, it is A.
By the way, Neeraj I think it is a DS qs and u should post it in DS section but not in PS!
Correct me If I am wrong


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by neeraj_99 » Sun Oct 28, 2007 11:58 pm
u r right...i sud have posted it there...ok...but IMO the ques. ask for terminating decimal...and as we know if the Denominator cosists of only 2 and 5, it must be terminating and hence finite no. of digits...pl. comment...
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by camitava » Mon Oct 29, 2007 12:46 am
Now if P < Q, then there is a probability that decimal equ. of P/Q = 0. But the Qs is looking for finite number of non-zero elements. So to me, it is A.
I did a mistake! I thought one option given in the option is P < Q but actually it was P > Q. Yop! Neeraj, I agree with u abt the fact that
as we know if the Denominator cosists of only 2 and 5, it must be terminating and hence finite no. of digits
. With 8 as denominator, in the worst case the result will come 3 digits after decimal i.e upto thousandth digit.
But I am really concerned about that particular word -
decimal equivalent of P/Q
. With Q = 8, it not possible to get the finite number of nonzero digits in decimal equivalent of P/Q because we don't know the value of P.
Similar with the case with P > Q. So IMO is E. Hey Neeraj, now at least refer the OA! :D
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by neeraj_99 » Mon Oct 29, 2007 9:47 am
thanx camitava, but i'm still confused...

What decimal equivalent of P/Q or any rational no. means? e.g. 1/4=0.25, is .25 not decimal equivalent of 1/4? if so, then how it matters what the value of P is? any value of P will make P/Q terminating decimal if Q=8

anyway, the OA is E, but why not B?[/list][/quote]
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by gabriel » Mon Oct 29, 2007 10:43 am
needless to say this is DS question and should be in the DS section ... moved to the DS section ..

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by gabriel » Mon Oct 29, 2007 10:48 am
btw the answer should be B .. P could be any value but if the denominator is of the form 2^a*5^b (over here b is 0) then the decimal equivalent of a fraction will have be terminating in nature .. So the answer should be B and not E ..

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by camitava » Mon Oct 29, 2007 8:15 pm
Gabriel, dnt mind! I already mentioned in my last post that I think, the issue is with the phrase - decimal equivalent of P/Q. I agree with the point what Neeraj and you raised. P/Q should have the result in worst case upto thousandth digit after decimal and
it will have be terminating in nature.
But if u again refer the Qs -
Does the decimal equivalent of P/Q, where P and Q are positive integers, contain only
a finite number of nonzero digits?
(1) P>Q
(2) Q=8
If Q = 8, we cannot predict on the decimal equ of P/Q. Ohhh, by the way, by the term decimal equ, I am taking that the result should be a whole number [after making approximation]. So I will still stand with E. Pls tell/ point me where I am wrong!
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by neeraj_99 » Mon Oct 29, 2007 10:50 pm
enough discussion on this ques...but unfortunately only among few of us...anyway...decimal equivalent of any rational no. wud be not whole no. but a terminating or non terminating no...

need clarification from the moderators...plz help
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by gabriel » Tue Oct 30, 2007 1:24 am
The decimal notation is nothing but representing a number in the base 10 .. so that could be a whole number or a fraction ( rational or irrational ) ... so the answer should be B ..

@ camitava .. i think ur confused with the definition of a decimal a decimal need not be just a integer it could also be a fraction as long as it is expressed in base 10 .. hope that helps ..

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by camitava » Tue Oct 30, 2007 1:29 am
Yop! Gabriel I was confused abt that particular word - decimal equ. I thought by decimal equ, the !s wants to say that the result is to be rounded off to make it a whole number. And that's why I argued so long. However, I am sorry for a mis-leading argument!
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Then how reliable is the OA of Set

by neeraj_99 » Tue Oct 30, 2007 4:07 am
Now when we're convinced that the right ans is B, can we say that the OA, which is E, is incorrect?
and if so, then how reliable r the GMAT set OA? I've come across atleast 4 to 5 prob, where OA seems to be incorrect.
More problematic is error in verbal, for it's more difficult to actually prove the OA wrong...and sometime it may shake one's confidence and weaken the concept...pl. share ur exp. on solving the GMAT sets....

in fact we can start a new thread, where doubtful OAs can be discussed.
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by camitava » Tue Oct 30, 2007 6:09 am
That's gr8 idea! But Neeraj I am not getting what are u trying to mean by GMAT set? I mean I am not getting the source!
Correct me If I am wrong


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by neeraj_99 » Tue Oct 30, 2007 9:59 am
GMAT SET are 30 nos. of full length actual GMAT mimicking question set widely available on the net...like esnip....or at score top....it is advisable to practice on these sets...source is not known...may be compiled by someone at ST...but i actually don know...
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by gmatrant » Fri Nov 02, 2007 8:12 pm
neeraj_99 wrote:GMAT SET are 30 nos. of full length actual GMAT mimicking question set widely available on the net...like esnip....or at score top....it is advisable to practice on these sets...source is not known...may be compiled by someone at ST...but i actually don know...
Was just going to the post ( a long one).. raking it up might be like bringing the dead back alive :).. but then..

if B is the right answer , then P can be equal to Q (since Q=8, P=8, so P/Q=1.0000), and in this case we have finite (or even infinite) number of zeroes and not non-zeroes as asked in the questions.So B as the answer is wrong. In case A, P>Q P can be 16 while Q can be 8 (so even if A and B are combined) there is a possibility of not getting finite number of non-zero decimals hence I guess the answer should be E.

Pls comment.