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Here`s a strange one.... If y is a positive integer, is 3y [#permalink]
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22 Apr 2006, 23:30
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Here`s a strange one....
If y is a positive integer, is 3y odd?
1. y+319 is even
2. y cannot be evenly divided by any odd number other than 1.



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Answer is D!
1. y+319 = even, hence y is odd (odd + odd > even). Thus 3y = oddxodd = odd!
2. Y is not an odd number. If it is odd, then Y should be divisible by 1 and by itself which is also odd!. But it says it is not divisble by any odd number, save 1. Thus it has to be even. Thus the 3x even = even!
Usually in GMAT both the options are congruent, ie they yield the same results. Here option 1 seems to indicate odd, while option 2 seems to indicate even! Thats kind of Weird for GMAT.
Where did you get this Q from? I have not seen this one in Kaplan though, which Kaplan is it?



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Re: WEIRD Kaplan DS [#permalink]
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23 Apr 2006, 07:54
GMATT73 wrote: Here`s a strange one.... If y is a positive integer, is 3y odd? 1. y+319 is even 2. y cannot be evenly divided by any odd number other than 1.
since y is a +ve integer,
from i, y is odd. so suff..
from ii, y is 1. also suff.
if y = 2, then 2 is evenly divided by 1 and 2. so only integer that is evenly (i guess evenly here doesnot mean 2, 4, 6 or so on) divided only by 1 is 1.
great question. D.



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Re: WEIRD Kaplan DS [#permalink]
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23 Apr 2006, 21:12
Professor wrote: GMATT73 wrote: Here`s a strange one.... If y is a positive integer, is 3y odd? 1. y+319 is even 2. y cannot be evenly divided by any odd number other than 1. since y is a +ve integer, from i, y is odd. so suff.. from ii, y is 1. also suff. if y = 2, then 2 is evenly divided by 1 and 2. so only integer that is evenly (i guess evenly here doesnot mean 2, 4, 6 or so on) divided only by 1 is 1. great question. D.
Great explanation professor.



Intern
Joined: 18 Apr 2006
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Well, it says it cannot be evenly divided by any ODD integer other than 1. So it may well be divisible by 2.
A



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Maxi2006 wrote: Well, it says it cannot be evenly divided by any ODD integer other than 1. So it may well be divisible by 2.
A
Be careful, evenly divided means divided without a remainder.
So the answer is 'D'.



Current Student
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Here is the confusing part with the wording in statement 2.
> y can either be 1 or an even number (2, 4, 8 ...) because they all divide evenly.
** If y = 1, then the answer to the stem is a definate YES.
<but>
** If y is an even number (also divisible by 1), then the answer to the stem is a definate NO.
Given these two possible conditions, how can both statements be sufficient (D)
BTW: This is from the "2005 Border`s Exclusive Edition" Kaplan prep text.
Last edited by GMATT73 on 24 Apr 2006, 07:22, edited 2 times in total.



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Re: WEIRD Kaplan DS [#permalink]
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24 Apr 2006, 07:12
GMATT73 wrote: Here`s a strange one....
If y is a positive integer, is 3y odd?
1. y+319 is even 2. y cannot be evenly divided by any odd number other than 1.
statement 2 means y is divisible by one and only one odd number that is 1.
> y can be 1 and 2 ( 4, 8 and all exponents of 2)
> 3y can be either odd or even
> insuff
A it should be.



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D is the answer.
From 1st option > we get 3y is odd
from 2nd option > y is even and 3y is even so suff.



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but from statement 2, y can also be 1



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Thanks for backing me up here Laxie Any other input guys?



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I agree. y=1 satisfies the second condition so we don't really know if 3y is odd or even for that one. In other word the answer should be A.
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yes the answer should be A
for B 1 and all other even numbers can satisfy the criteria ...



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3y is odd only if y is odd. So the question si asking if y is odd.
1) y+319 is even. 319 is odd. So y must be odd. Sufficient.
2) y is prime, which could be odd (any primes other than 2) or not odd(the prime number 2). Insufficient.
Ans A



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Re: WEIRD Kaplan DS [#permalink]
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24 Apr 2006, 20:57
GMATT73 wrote: Here`s a strange one....
If y is a positive integer, is 3y odd?
1. y+319 is even 2. y cannot be evenly divided by any odd number other than 1.
good question...what is the OA?



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Joined: 16 Apr 2006
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I read ii to mean y is prime as well but since it does not exclude 2 than it is not suff so A



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The OA, according to Kaplan is (D). I am still not convinced...



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GMATT73 wrote: The OA, according to Kaplan is (D). I am still not convinced...
But as we know, Kaplan is sometimes very erroneous



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laxieqv wrote: GMATT73 wrote: The OA, according to Kaplan is (D). I am still not convinced... But as we know, Kaplan is sometimes very erroneous
buddy, our math experts has cleared the confusion and misconception that D is not correct.
it was indeed a great discussion.



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Professor wrote: laxieqv wrote: GMATT73 wrote: The OA, according to Kaplan is (D). I am still not convinced... But as we know, Kaplan is sometimes very erroneous buddy, our math experts has cleared the confusion and misconception that D is not correct. it was indeed a great discussion.
buddy, this time, the merit goes to Matt as he pointed out the confusion and put forward a thorough consideration
If we stay alert like Matt, keeping an eye on any trickiness of GMAT, we'll certainly ace the maths section







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