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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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29 May 2014, 22:55
shagalo wrote: VeritasPrepKarishma wrote: shagalo wrote: can any one tell me why (1) and (2) are insufficient ? (1) shows that the set is …. 16,8,4,,2,4,8,16….( there is no 12 here) so it is sufficient. (2) shows that the set is …. 27,9,3,3,9,27,…… ( there is no 12 here) so it is sufficient. so the answer is D … each alone is sufficient.
any explanation please? thanks How does statement 1 show that 12 is not in the set? All statement 1 tells you is that 2 is there and hence 2 is there. We don't know anything about other elements. How did you get 4, 8 etc. We are not given that if 2 is there, only powers of 2 will be there.  Sorry but your explanation is not clear. and i got these numbers " 16,8,4,,2,4,8,16…" after applying the statement (1) on the equation (i) and (ii). what i understood is that if you applied statement (1) "2 in K", then you will get this set of numbers " 16,8,4,,2,4,8,16…" which do not include 12. the same apply on statement (2). could you explain what is the flaw in my understanding. Thanks Given: (i) If x is in K, then x is in K, and (ii) if each of x and y is in K, then xy is in K Stmnt 1: 2 is in K This implies 2, 2, 4 (2*2), 8 (2*4), 8 (2*4), etc are in the set. 4 will not be there. But how do you know that no other elements are there in the set? Could we have a set like this: {12, 2, 24, 2, 12, 24 ...} Does it satisfy all 3 conditions given above? Yes. The set {2, 2, 4, 8, ...} satisfies all 3 conditions too. Hence we don't know what the set actually looks like. Just because the set has 2 doesn't mean it cannot have 12.
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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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01 Jun 2014, 00:46
K is a set of numbers such that (i) If x is in K, then x is in K, and (ii) if each of x and y is in K, then xy is in K Is 12 in K? (1) 2 is in K (2) 3 is in K Statement 1) if 2 is in K, then 2 should be in K. Is 12 in K ? Not sufficient Statement 2) Same as above not sufficient. Both the statement) 2 is in K, then 2 is in K. 3 is in K, 3 is in K 2 and 3 both are in K, then 6 is in K Till now we have K has {2,3,2,3,6} Now as 6 is in K and also 2 is also in K, 12 has to be in K Hence Sufficient  Option C)
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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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29 Sep 2015, 04:45
Hi Bunuel, Could please post the correct question . I think there is power missing in the main question here . Please repost the correct question .
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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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29 Sep 2015, 04:52



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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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15 Jul 2016, 11:19
K is a set of numbers such that (i) If x is in K, then x is in K, and (ii) if each of x and y is in K, then xy is in K Is 12 in K? (1) 2 is in K According to the restrictions if 2 (i.e " x") is in Set K then 2(i.e. "x") should also be in Set K since 2 and 2 are technically different numbers you can consider them x and y. Now (xy)= 2 * 2 = 4 should be there. Since 4 is there then its negative counterpart should be there too i.e "(4)" =4 and so on K={2,2, 4,4,8,8,16,16,32,32,........} Insufficient , we don not know apart from 2 and it's derivative what other numbers are inside Set K. (2) 3 is in K According to the restrictions if 3 is in k then 3 should also be in K K={3,3,9,9,27,27,81,81.. } Insufficient , we do not know apart from 2 and it's derivative what other numbers are inside K Merge both K={2,2,3,3,4,4,6,6,12,12,24,24,27,27...} SUFFICIENT ANSWER IS C
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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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18 Sep 2016, 06:52
Bunuel wrote: afyl128 wrote: My First post K is a set of numbers such that (i) If x is in K, then x is in K, and (ii) if each of x and y is in K, then xy is in K Is 12 in K? (1) 2 is in K (2) 3 is in K for (1) know that 2, 2 is in K for (2) know that 3, 3 is in K Together have [3, 2, 2, 3, 6] So I would say neither is sufficient?? Hi, and welcome to the club. Below is the solution for your problem. (1) 2 is in K > according to (i) 2 is n K > according to (ii) 2*2=4 is in K > according to (i) (4)=4 is in K and so on. Thus we know that 2, 2, 4, 4, 8, 8, 16, 16, ... are in K, so basically powers of 2 and their negative pairs. Is 12 in K? We don't know. Not sufficient. (2) 3 is in K > according to (i) 3 is n K > according to (ii) 3*3=9 is in K > according to (i) (9)=9 is in K and so on. Thus we know that 3, 3, 9, 9, 27, 27, 81, 81, ... are in K, so basically powers of 3 and their negative pairs. Is 12 in K? We don't know. Not sufficient. (1)+(2) From (1) 4 is in K and from (2) 3 is in K, hence according to (ii) 4*3=12 must also be in K. Sufficient. Answer: C. Hope it's clear. When I was working on this questions I understood from statement 1+2 that 12 could be on the set. But as he asks: is 12 in the set? Well I assumed it could be in the set or not, why can I assume the set is not finite? I got a similar Gmat question wrong for assuming the opposite.



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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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18 Sep 2016, 09:30
Coruja wrote: Bunuel wrote: afyl128 wrote: My First post K is a set of numbers such that (i) If x is in K, then x is in K, and (ii) if each of x and y is in K, then xy is in K Is 12 in K? (1) 2 is in K (2) 3 is in K for (1) know that 2, 2 is in K for (2) know that 3, 3 is in K Together have [3, 2, 2, 3, 6] So I would say neither is sufficient?? Hi, and welcome to the club. Below is the solution for your problem. (1) 2 is in K > according to (i) 2 is n K > according to (ii) 2*2=4 is in K > according to (i) (4)=4 is in K and so on. Thus we know that 2, 2, 4, 4, 8, 8, 16, 16, ... are in K, so basically powers of 2 and their negative pairs. Is 12 in K? We don't know. Not sufficient. (2) 3 is in K > according to (i) 3 is n K > according to (ii) 3*3=9 is in K > according to (i) (9)=9 is in K and so on. Thus we know that 3, 3, 9, 9, 27, 27, 81, 81, ... are in K, so basically powers of 3 and their negative pairs. Is 12 in K? We don't know. Not sufficient. (1)+(2) From (1) 4 is in K and from (2) 3 is in K, hence according to (ii) 4*3=12 must also be in K. Sufficient. Answer: C. Hope it's clear. When I was working on this questions I understood from statement 1+2 that 12 could be on the set. But as he asks: is 12 in the set? Well I assumed it could be in the set or not, why can I assume the set is not finite? I got a similar Gmat question wrong for assuming the opposite. The stem gives clear description of the set and it's not saying that the set is finite.
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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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23 Dec 2017, 18:43
can someone please explain this question from the basic. i am not able to understand how is the set{....,16,8,4,2,2,4,8,16,....} or the set {....,81,27,9,3,3,9,27,81,...} is made.



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Re: K is a set of numbers such that (i) If x is in K, then x [#permalink]
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24 Dec 2017, 00:36
tusumathur1995 wrote: can someone please explain this question from the basic. i am not able to understand how is the set{....,16,8,4,2,2,4,8,16,....} or the set {....,81,27,9,3,3,9,27,81,...} is made. Expert solutions: https://gmatclub.com/forum/kisaseto ... ml#p746627https://gmatclub.com/forum/kisaseto ... l#p1157125Similar questions to practice PS: http://gmatclub.com/forum/asetofnumb ... 98829.htmlhttp://gmatclub.com/forum/foracertain ... 36580.htmlhttps://gmatclub.com/forum/foracertai ... 61920.htmlhttps://gmatclub.com/forum/asetofnum ... 60975.htmlhttps://gmatclub.com/forum/asetofnum ... 68728.htmlDS: https://gmatclub.com/forum/kisaseto ... 66908.htmlhttp://gmatclub.com/forum/ifpisaset ... 96630.htmlhttp://gmatclub.com/forum/kisasetof ... 03005.htmlhttps://gmatclub.com/forum/sisaseto ... 30000.htmlhttps://gmatclub.com/forum/sisaseto ... 31344.htmlhttps://gmatclub.com/forum/sisaseto ... 09986.htmlhttps://gmatclub.com/forum/sisaseto ... 46777.htmlOPEN DISCUSSION OF THIS QUESTION IS HERE: https://gmatclub.com/forum/kisaseto ... 66908.html
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