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DS  POSITIVE INTEGER (m04q17) [#permalink]
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03 Sep 2008, 14:34
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This topic is locked. If you want to discuss this question please repost it in the respective forum. Is integer \(R\) positive? 1. \(R^3 = R\) 2. \(R = R\) Source: GMAT Club Tests  hardest GMAT questions
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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 14:36
B
from 1 : two possibilities 1,1
from 2 : has to be +ve else not possible



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 14:38
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Again E. 1) R=0 or R=+1 2) R=0 or Any positive #, including 1
1+2) still R=0 or R=1 So E.



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 14:52
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IMO E.
At 1st I thought it will be B, but ya if R=0, that screws up evrything..



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 17:15
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Hmm I am getting B for this. This is Yes/No DS and a No answer is sufficient
We all agree on A is insuff. R ^ 3  R = 0, which means R =0, 1 ,1 ( No, Yes, No for the Q Is R +ve? ) hence Insuff
B is saying
R = R and R = R (R is integer)
Lets say R =1 R = 1 which is not equal to R same thing for any ve integer
The only number I can think of satisfying the above two equations is 0
Is 0 positive? No ( neither positive nor negative) . Hence B.
Do you agree? Did I go wrong any where?



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 18:00
R=R means R=R when ris +ve and R=R, when R is ve
so, option gives you all the +ve integers + 0



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 19:16
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I'm getting E for this problem as well.
(1) R could be negative, zero, or even positive.
(2) R could be positive or zero.
(1&2) R could still be positive or Zero
So our answer is E.



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 20:16
Yeap E is the answer! Thanks for discussion. I chose B making another stupid mistake.. considered "zero" as +ve.. RULE IS "ZERO is neither positive nor negative"
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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 21:04
K! Seriously I need some enlightenment as I am totally lost here.
When I see a absolute variable I create 2 equations and we are given that R is integer and  R  = R
I read it as Can you find integer(s) such that R = R and R = R
For all integers positive and negative I can say R is not equal to R except for 0
0 is the integer that satisfies both R = R and R = R
0 is neither +ve nor ve. Going back to the Q Is R positive? NO
I felt that its sufficient and chose B.
Can some one explain where I am going wrong?



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 21:11
icandy wrote: K! Seriously I need some enlightenment as I am totally lost here.
When I see a absolute variable I create 2 equations and we are given that R is integer and  R  = R
I read it as Can you find integer(s) such that R = R and R = R
For all integers positive and negative I can say R is not equal to R except for 0
0 is the integer that satisfies both R = R and R = R
0 is neither +ve nor ve. Going back to the Q Is R positive? NO
I felt that its sufficient and chose B.
Can some one explain where I am going wrong? R=R one solution for this is R=0 other solutions when R>0 R=R So R is +ve when R<0 R=R > invalid so R can't be ve So all together two solutions R=0 or R is +ve Is R Positive? No when R=0 Is R Positive? Yes when R is +ve insuffcient.
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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 21:33
x2suresh wrote: icandy wrote: K! Seriously I need some enlightenment as I am totally lost here.
When I see a absolute variable I create 2 equations and we are given that R is integer and  R  = R
I read it as Can you find integer(s) such that R = R and R = R
For all integers positive and negative I can say R is not equal to R except for 0
0 is the integer that satisfies both R = R and R = R
0 is neither +ve nor ve. Going back to the Q Is R positive? NO
I felt that its sufficient and chose B.
Can some one explain where I am going wrong? R=R one solution for this is R=0 other solutions when R>0 R=R So R is +ve when R<0 R=R > invalid so R can't be ve So all together two solutions R=0 or R is +ve Is R Positive? No when R=0 Is R Positive? Yes when R is +ve insuffcient. Now I see what I am doing differently. When I look at R = R and consider the two equations I am considering that both the cases of R = R and R = R needs to be satisfied. What needs to be checked is whether I arrive at same answer in all three cases. Thanks.



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Re: DS  POSITIVE INTEGER [#permalink]
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03 Sep 2008, 21:44
x2suresh wrote: Is integer R positive?
1.R^3=R 2.R= R 1: r could be 0 or 1. 2: r could be 0 or any +ve. 1&2: o or 1. nsf. E.
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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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24 Jul 2010, 05:25
Yep. Answer is E. The rule tested here is: 0 is neither +ve nor ve
Cheers! Ravi



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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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28 Jul 2011, 06:32
Simply test +1, 1, and 0 here to get answer. E



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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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31 Jul 2012, 12:06
Seemed really easy to lead to B. I made the silly mistake and did not consider 0 for the statement (ii). Realized my mistake and learnt from it.
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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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31 Jul 2012, 21:48
is it something like /0/ does not exist or the value of /0/ is again a zero which is neither positive nor negative???
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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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02 Aug 2012, 00:53



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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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31 Jul 2013, 10:52
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x2suresh wrote: Is integer \(R\) positive? 1. \(R^3 = R\) 2. \(R = R\) Source: GMAT Club Tests  hardest GMAT questions Is integer R positive?(1) R^3=R > \(r^3r=0\) > \(r(r^21)=0\) > \(r(r1)(r+1)=0\) > \(r=0\), \(r=1\), or \(r=1\). Not sufficient. (2) R=R > \(r\) is some nonnegative integer, so \(r\) can be 0 or any positive integer. Not sufficient. (1)+(2) \(r\) can be 0, so not a positive integer or 1, a positive integer, two different answers, hence not sufficient. Answer: E.
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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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26 Oct 2013, 03:23
Hello Bunuel,
Can you please tell me if "0" is a positive even integer or not.
The notes of GMAT Club Math book does say that 0 is an even positive integer, but in this question, we again differ with it.
Can you please clarify this doubt of mine. Appreciate it



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Re: DS  POSITIVE INTEGER (m04q17) [#permalink]
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26 Oct 2013, 03:42




Re: DS  POSITIVE INTEGER (m04q17)
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