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OG problem quant 2nd edition

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OG problem quant 2nd edition

by Redhorsep » Wed Sep 14, 2011 10:19 am
Hi,

I never saw this type of problem before until it came up in the OG quant 2nd edition. Please explain your solutions. I don't really understand the OG one. Thanks!

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
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Source: — Data Sufficiency |
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by cans » Wed Sep 14, 2011 10:31 am
K={a,b,c,.............}
K is set of numbers.
rule 1: if x is present, -x is also present.
Thus if -1 is in K, we have 1 also. if we have 2, we have -2 also...
rule 2: if 2,3 are present: 6 is also present. And now as 2 and 6 are present, 12 should be present and similarly 24 should be present and so on it will continue.

12???
a) 2 is in K. thus -2 is also there and thus -4 is also there (rule 2) and thus 4 is there and so on..
by this we can get any power of 2. but we don't know whether 3 is there or not
Insufficient

b) 3 is in K. With this we can get any power of 3, but again absence of 2 means we can't say whether 12 is there or nor.

a&b) 2,3 means 6 is there and that means 12 is there
IMO C
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by sl750 » Wed Sep 14, 2011 12:18 pm
We have to use the 2 rules to generate a set of elements and conclude whether 12 is present in the set or not

Statement 1 (Uses both rules)
K = {2,-2,-4,4,-16,...}. From this we can see that 12 is not present in the set. Sufficient

Statement 2 (Uses both rules)
K = {3,-3,-9,9,81,...}. Sufficient
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by prateek_guy2004 » Wed Sep 14, 2011 1:27 pm
I agree its a different type of ques....I also guessed C
Don't look for the incorrect things that you have done rather look for remedies....

https://www.beatthegmat.com/motivation-t90253.html
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by 1947 » Wed Sep 14, 2011 7:47 pm
yup C
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by mankey » Fri Nov 04, 2011 11:14 am
IMO: D

Proceeded with the same solution as that of sl750. Please provide OA.

Thanks.
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