IMO A
if any prime no. -z=odd no. then z is an even no.
becoz all prime no's except 2 are odd hence in order to get an odd z must be an even
hence xyz is not an odd no.
suff
s2) does not tells anything abt z
hence insuff
is xyz odd ?
Source: Beat The GMAT — Data Sufficiency |
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thephoenix
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neoreaves
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Nope....OA is Cthephoenix wrote:IMO A
if any prime no. -z=odd no. then z is an even no.
becoz all prime no's except 2 are odd hence in order to get an odd z must be an even
hence xyz is not an odd no.
suff
s2) does not tells anything abt z
hence insuff
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thephoenix
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[email protected]
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statement (1) says
Any prime number - Z = Positive Odd number
Z= Any prime number - Positive Odd number
=(5,7,11,13,17....) - (3,5,7,9....)
=is even
statement 1 is sufficient
statement (2)
if we take any number =X, then X+1=Prime, means X can be 1,4,6,10,12....... where X+1 is 2,5,7,11,13.....
since the original question already says X>Y>Z and all are positive integers, X is definitely greater than 1, which means X=4,6,10
It is given that XYZ is not divisible by 4, X can be 6,10....
SO statement 2 is sufficient
so answer should be D
Any prime number - Z = Positive Odd number
Z= Any prime number - Positive Odd number
=(5,7,11,13,17....) - (3,5,7,9....)
=is even
statement 1 is sufficient
statement (2)
if we take any number =X, then X+1=Prime, means X can be 1,4,6,10,12....... where X+1 is 2,5,7,11,13.....
since the original question already says X>Y>Z and all are positive integers, X is definitely greater than 1, which means X=4,6,10
It is given that XYZ is not divisible by 4, X can be 6,10....
SO statement 2 is sufficient
so answer should be D
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kstv
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either way if z is even xyz or x*y*z will be even.thephoenix wrote:is it x*y*z or xyz
do u have OE
if it is x*y*z then alteast two of them are odd otherwise it will be divisible by 4
(1) Any prime number - Z = Positive Odd number and z < y < x
so possible z = 1 (cos 2 is a prime no) or even nos. Insuff
(2) X +1 = Prime and X, Y, Z are positive integers X>Y>Z
x > 3 cos even if z = 1 x will be 3 but since x + 1 = prime no and all prime no except 2 is an odd no
x has to be an even number > 3 i.e. 4, 6, 8
so x*y*z will be an even no. Sufficient.
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thephoenix
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Ok agreed with you soln for s1) but if its xyz a three digit no. then does s2) is sufficient , i dont think sokstv wrote: (2) X +1 = Prime and X, Y, Z are positive integers X>Y>Z
x > 3 cos even if z = 1 x will be 3 but since x + 1 = prime no and all prime no except 2 is an odd no
x has to be an even number > 3 i.e. 4, 6, 8
so x*y*z will be an even no. Sufficient.
however the poster says OA is C
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November Rain
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I think Statement 1 is wrong because otherwise its an impossible condition.1) Any prime number - Z = Positive Odd number
If the prime number is 2, then Z needs to be 1(odd) so that the result is a positive odd number
If the prime number is other than 2, then Z needs to be an even number so that the result is a positive odd number.
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ISBcalling
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As XYZ is not divisible by 4 thus any of X,Y,Z can't be 4 or its multiple. On top of this, if any one is even, the other two has to be odd.
From option 1, Z = Any Prime no. - positive odd int ------------ Here prime no. can't be same as odd int but odd int cud be a prime.
=> Z = {(2-1), (3-1), (5-3), (7-1), (11-1), (11-5), (13-3), (13-7) etc} = {1, 2, 6, 10 etc}
Option 1 is insufficient as it shows z can be odd as well as even.
From Option 2, X+1 is prime. Here X can neither be 1 nor be 2 as X>Y>Z and all are positive integers.
X can be 3, 6, 10, 18 etc but can't be 4 or its multiple.
Option 2 is also insufficient as X can be odd as well as even.
Combining Option 1 & 2, X+1 is prime & Z = Any prime no. - positive int.
Both X & Z can't be even. If X = 3, Z could only be 1.
If X = 6, Z could be only 1 & can't be 2.
If X = 10, Z could be only 1.
X could be both odd as well as even, Z will be only 1.
Thus Option 1 & 2 together is also insufficient.
My Answer is E.
From option 1, Z = Any Prime no. - positive odd int ------------ Here prime no. can't be same as odd int but odd int cud be a prime.
=> Z = {(2-1), (3-1), (5-3), (7-1), (11-1), (11-5), (13-3), (13-7) etc} = {1, 2, 6, 10 etc}
Option 1 is insufficient as it shows z can be odd as well as even.
From Option 2, X+1 is prime. Here X can neither be 1 nor be 2 as X>Y>Z and all are positive integers.
X can be 3, 6, 10, 18 etc but can't be 4 or its multiple.
Option 2 is also insufficient as X can be odd as well as even.
Combining Option 1 & 2, X+1 is prime & Z = Any prime no. - positive int.
Both X & Z can't be even. If X = 3, Z could only be 1.
If X = 6, Z could be only 1 & can't be 2.
If X = 10, Z could be only 1.
X could be both odd as well as even, Z will be only 1.
Thus Option 1 & 2 together is also insufficient.
My Answer is E.
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Stuart@KaplanGMAT
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The question isn't formatted as a GMAT question would be - on the GMAT, the extra information in the stem always precedes the question. For example:neoreaves wrote:Is XYZ an odd number? Where X, Y, Z are positive integers
Such that XYZ is not divisible by 4 and X>Y>Z
1) Any prime number - Z = Positive Odd number
2) X +1 = Prime
What's the source? Statement (1) provides an impossible condition, so you (and others) should be very wary of this source in the future.If X, Y and Z are positive integers, XYZ is not divisible by 4 and X > Y > Z, is XYZ odd?
Always citing your sources accomplishes 3 things:
1) you give credit to the question creator, thereby avoiding plagiarism issues;
2) you tell the reader how credible (i.e. "GMATesque") the question is; and
3) you help people avoid unreliable sources in the future.
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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Stuart@KaplanGMAT
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One small math point (even though this is a bad question, we can still learn a few things from it!):ISBcalling wrote: From Option 2, X+1 is prime. Here X can neither be 1 nor be 2 as X>Y>Z and all are positive integers.
X can be 3, 6, 10, 18 etc but can't be 4 or its multiple.
Option 2 is also insufficient as X can be odd as well as even.
if X+1 is prime, then x could be:
1, 2, 4, 6, 10, ...
However, since X>Y>Z>0, the smallest possible value of X (ignoring statement (2)) is 3.
So, the values of X based on statement (2) are:
4, 6, 10, 12, ....
every one of which is even.
(We could also eliminate all the multiples of 4, but that's irrelevant to answering the question.)
If X must be even, then XYZ will always be even as well, providing a definite "no" answer to the original question.
Accordingly, (2) is sufficient alone.
(Statement (1) is impossible, since there's no value of Z that fits the condition given, so there's no sense evaluation (1).)
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neoreaves
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again the source is some other forum ...... but then again isnt the purpose of a forum to discuss ...no matter how absurd a question is ...the important thing is to find the right answer ....... it was not my intention to lead people astray in case it was a non GMAT-esque question ........but again if i have encountered a problem quoted on some forum by someone and it confused me ....why not discuss it out with everyone ....it clears my concepts as well as other people's concepts .....i am sure discussing a bad question is still better than not discussing it ....
Moreoever, i know such questions with the incorrect OA can confuse us but with valuable feedbacks specially from Instructors we can see our way through ...which was the same in this case .....
I agree the question is not very GMAT-esque ...and if it was then OA should be B ..though statement 1 is impossible
Moreoever, i know such questions with the incorrect OA can confuse us but with valuable feedbacks specially from Instructors we can see our way through ...which was the same in this case .....
I agree the question is not very GMAT-esque ...and if it was then OA should be B ..though statement 1 is impossible
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kstv
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I may have just scratched the surface of GMAT , forget Beating it . Still, I do feel stating the source is imp. Even if you state at the beginning that you are not sure of the source.
Then one does not get psyched if you do not make progress after spending 5 mins on one Q.
Try solving a dubious SC Q in verbal, you may just end up with a wrong concept.
There are some grammer rules which are unique to GMAT or so I console myself.
Yes, nothing like thrashing out wrong concepts at this forum.
Hope to see more posts from you.
Then one does not get psyched if you do not make progress after spending 5 mins on one Q.
Try solving a dubious SC Q in verbal, you may just end up with a wrong concept.
There are some grammer rules which are unique to GMAT or so I console myself.
Yes, nothing like thrashing out wrong concepts at this forum.
Hope to see more posts from you.
I think I am missing something, but cant put a finger on it. Stmt 1 says:
1) Any prime number - Z = Positive Odd number
Not able to figure out why it is impossible - what if Z = 2? any other Prime number would be an odd number.
This implies the difference would be a Positive odd number, since Z is the least of the three.
1) Any prime number - Z = Positive Odd number
Not able to figure out why it is impossible - what if Z = 2? any other Prime number would be an odd number.
This implies the difference would be a Positive odd number, since Z is the least of the three.
