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If k is an integer greater than 1, is k equal to 2^r for [#permalink]
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27 Oct 2008, 10:49
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If k is an integer greater than 1, is k equal to \(2^r\) for some positive integer r? (1) k is divisible by \(2^6\) (2) k is not divisible by any odd integer great than 1 Please explain your answer. Thanks == Message from GMAT Club Team == This is not a quality discussion. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 11:01
1)you can have 192/64 or 128/64 so insuff 2) K is even, insuff
together insuff
E



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 11:10
tarek99 wrote: If k is an integer greater than 1, is k equal to \(2^r\) for some positive integer r?
(1) k is divisible by \(2^6\)
(2) k is not divisible by any odd integer great than 1
Please explain your answer.
Thanks I will go for (B) (1) When k= 2^8, then, Yes. When k= 3* 2^8, then No. Insuff (2) Any integer not divisible by an odd integer greater than 1 could be represented in the form 2^r. Hence suff. I couldn't think of any example otherwise.
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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 11:29
leonidas wrote: tarek99 wrote: If k is an integer greater than 1, is k equal to \(2^r\) for some positive integer r?
(1) k is divisible by \(2^6\)
(2) k is not divisible by any odd integer great than 1
Please explain your answer.
Thanks I will go for (B) (1) When k= 2^8, then, Yes. When k= 3* 2^8, then No. Insuff (2) Any integer not divisible by an odd integer greater than 1 could be represented in the form 2^r. Hence suff. I couldn't think of any example otherwise. I didn't understand your analysis of statement 2. Would you please explain how? thanks



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 11:31
If k is an integer greater than 1, is k equal to 2^r for some positive integer r?
(1) k is divisible by \(2^6\)
(2) k is not divisible by any odd integer great than 1
from one
K = x*2^6............x can = 2 or any intiger..........insuff
from2
k is intiger and it is not deviable by any odd intiger ( it can be odd eg 7/5) or even ( 4/3)...insuff
both
K =X*2^6 AND STILL X CAN BE ODD OR EVEN.........INSUFF
E



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 11:40
tarek99 wrote: leonidas wrote: tarek99 wrote: If k is an integer greater than 1, is k equal to \(2^r\) for some positive integer r?
(1) k is divisible by \(2^6\)
(2) k is not divisible by any odd integer great than 1
Please explain your answer.
Thanks I will go for (B) (1) When k= 2^8, then, Yes. When k= 3* 2^8, then No. Insuff (2) Any integer not divisible by an odd integer greater than 1 could be represented in the form 2^r. Hence suff. I couldn't think of any example otherwise. I didn't understand your analysis of statement 2. Would you please explain how? thanks => It is easy for us to find an integer greater than 1 that is not divisible by an odd interger (>1) and represent it in the form of 2^r. For example 2^8 is not divisible by any odd integer. =>In order to prove that (2) is insuff, we have to find an integer which is not divisble by an odd integer and that cannot be represented in the form of 2^r. There is no number greater than 1 which satisfies this condition. Any integer which cannot be divisible by an odd integer is an even integer which can be represented in the form of 2^r. Not sure, if I confused you more
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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 12:53
i too think ans should be E..
K>1 thats what the stem says..its positive,
2) says its not a multiple of any odd integer which means k=2^r
we could have something like 7/5



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 17:21
tarek99 wrote: If k is an integer greater than 1, is k equal to \(2^r\) for some positive integer r?
(1) k is divisible by \(2^6\)
(2) k is not divisible by any odd integer great than 1
Please explain your answer.
Thanks k = some positive integer greater than 1 the question stem is asking is k of the form \(2^r\). When will it be of this form ? when it has only 2 as its prime factor. (1) k is divisible by \(2^6\). This just means k has \(2^6\) as its factor, but it does not say this is the ONLY factor. There could be some odd factors as well ! (2) k is not divisible by any odd integer > 1. This means k has only even factors. When you have only even factors, it can be written in the \(2^x\) form. I pick B.
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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 17:28
amitdgr wrote: (2) k is not divisible by any odd integer > 1. This means k has only even factors. When you have only even factors, it can be written in the \(2^x\) form.
I pick B.
Let's say k has 6 as a factor. which means k = 6L with out knowing L we can't write k in the form of 2 ^ r for example if L=3, K=18 Can 18 be written as a factor of 2 ^ r? NO. if k=8L and L =4 K= 2 ^ 5. Am I doing any thing wrong?



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 17:36
icandy wrote: amitdgr wrote: (2) k is not divisible by any odd integer > 1. This means k has only even factors. When you have only even factors, it can be written in the \(2^x\) form.
I pick B.
Let's say k has 6 as a factor. which means k = 6L with out knowing L we can't write k in the form of 2 ^ r for example if L=3, K=18 Can 18 be written as a factor of 2 ^ r? NO. if k=8L and L =4 K= 2 ^ 5. Am I doing any thing wrong? The way i understood the statement in the problem, if k has only even factor, it has only even prime factors. k=6 means k has 3 as one of its factors. I may be completely wrong.
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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 17:50
amitdgr wrote: icandy wrote: amitdgr wrote: (2) k is not divisible by any odd integer > 1. This means k has only even factors. When you have only even factors, it can be written in the \(2^x\) form.
I pick B.
Let's say k has 6 as a factor. which means k = 6L with out knowing L we can't write k in the form of 2 ^ r for example if L=3, K=18 Can 18 be written as a factor of 2 ^ r? NO. if k=8L and L =4 K= 2 ^ 5. Am I doing any thing wrong? The way i understood the statement in the problem, if k has only even factor, it has only even prime factors. k=6 means k has 3 as one of its factors. I may be completely wrong. Ok. I get it. I got it wrong. K cannot have 6 as a factor because it will automatically make 3 a factor and that is not in line with (2) That makes only 2 the remaining factor.



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Re: DS: Try this GMATprep problem [#permalink]
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27 Oct 2008, 17:52
Agree with amitdgr. "k is not divisible by any odd integer great than 1" Can someone show an integer which is not divisible by an odd integer(>1) and which could not be expressed in the form of 2^r? Is k equal to 2^r? is a YES from (2).
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Re: DS: Try this GMATprep problem [#permalink]
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28 Oct 2008, 16:36
Initially I had picked E Changed to B Good problem tarek99, and good explanation leonidas +1 for both of you



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Re: DS: Try this GMATprep problem [#permalink]
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28 Oct 2008, 16:43
Ahh the key word is any odd integer.. I initially went with B and changed to E but now I agree with B == Message from GMAT Club Team == This is not a quality discussion. It has been retired. If you would like to discuss this question please repost it in the respective forum. Thank you! To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative  Verbal Please note  we may remove posts that do not follow our posting guidelines. Thank you.




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