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S is a set of integers such that i) if a is in S, then a is
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24 Feb 2011, 14:15
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S is a set of integers such that i) if a is in S, then –a is in S, and ii) if each of a and b is in S, then ab is in S. Is –4 in S? (1) 1 is in S. (2) 2 is in S.
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Re: S is a set of integers such that i) if a is in S, then a is
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24 Feb 2011, 14:28



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Re: S is a set of integers such that i) if a is in S, then a is
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24 Feb 2011, 14:30
(1) 1 is in S. Thus, 1 is there. If 1 and 1 are there; then 1*1=1 is there; We don't know anything other than that. 4 may or may not be there. Sufficient. (2) 2 is in S. Thus, 2 is there. If 2 and 2 are both there, 4 must be there. We know 4 is there. Don't care about anything else. Sufficient. Ans: "B"
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Re: S is a set of integers such that i) if a is in S, then a is
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22 Mar 2016, 02:24
Sorry, I am lost here, if we know that a =2 then how do we now that b= 2 ? to reach the conclusion that 4 is in S.
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Re: S is a set of integers such that i) if a is in S, then a is
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22 Mar 2016, 03:01
sony1000 wrote: Sorry, I am lost here, if we know that a =2 then how do we now that b= 2 ? to reach the conclusion that 4 is in S. Hi, you don't require to know what is a or what is b.. a and b are just two integers in the SET... similarly when we know 2 is there, 2 will be there.. if 2 and 2 are there, 2*2=4 is there..
further if 4 is there, 4 is there.. so 4*4=16 is also there.. also 2*4=8 is there.. and so on
so a and b stand for any two integers in the set..
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Re: S is a set of integers such that
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30 Dec 2018, 18:23
S is a set of integers such that i) if a is in S, then –a is in S, and ii) if each of a and b is in S, then ab is in S. Is –4 in S? (1) 1 is in S > according to (i) 1 is in S. Is 4 in S? We don't know. Not sufficient. (2) 2 is in S > according to (i) 2 is in S > according to (ii) 2*2=4 is in S. Sufficient. Answer: B. Posted from my mobile device
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Re: S is a set of integers such that
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31 Dec 2018, 02:33
gmatbusters wrote: S is a set of integers such that i) if a is in S, then –a is in S, and ii) if each of a and b is in S, then ab is in S. Is –4 in S?
(1) 1 is in S > according to (i) 1 is in S. Is 4 in S? We don't know. Not sufficient.
(2) 2 is in S > according to (i) 2 is in S > according to (ii) 2*2=4 is in S. Sufficient.
Answer: B.
Posted from my mobile device How do we know a equals b in this case? I find the wording quite confusing
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Re: S is a set of integers such that
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31 Dec 2018, 14:38
Arro44 wrote: gmatbusters wrote: S is a set of integers such that i) if a is in S, then –a is in S, and ii) if each of a and b is in S, then ab is in S. Is –4 in S?
(1) 1 is in S > according to (i) 1 is in S. Is 4 in S? We don't know. Not sufficient.
(2) 2 is in S > according to (i) 2 is in S > according to (ii) 2*2=4 is in S. Sufficient.
Answer: B.
Posted from my mobile device How do we know a equals b in this case? I find the wording quite confusing "if each of a and b is in S, then ab is in S." All this means is that if 2 integers are in S, then the product of those 2 integers is in S.



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Re: S is a set of integers such that
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13 Jan 2019, 21:24
gmatbusters wrote: Project DS Butler: Day 54: Data Sufficiency (DS108) For DS butler Questions Click HereS is a set of integers such that i) if a is in S, then a is in S, and ii) if each of a and b is in S, then ab is in S. Is 4 in S? (1) 1 is in S. (2) 2 is in S Dear Moderator, This same question has been repeated in the link below , you may wish to merge the same. Thank you. https://gmatclub.com/forum/sisaseto ... 09986.html
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Re: S is a set of integers such that i) if a is in S, then a is
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13 Jan 2019, 21:27
stne wrote: gmatbusters wrote: Project DS Butler: Day 54: Data Sufficiency (DS108) For DS butler Questions Click HereS is a set of integers such that i) if a is in S, then a is in S, and ii) if each of a and b is in S, then ab is in S. Is 4 in S? (1) 1 is in S. (2) 2 is in S Dear Moderator, This same question has been repeated in the link below , you may wish to merge the same. Thank you. https://gmatclub.com/forum/sisaseto ... 09986.html_______________________ Topics merged. Thank you.
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Re: S is a set of integers such that i) if a is in S, then a is
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