If y ≠3 and 3x/y is a prime integer greater than 2, which of the following must be true?
â… . x = y
â…¡. y = 1
â…¢. x and y are prime integers.
(A) None
(B) â… only
(C) â…¡only
(D) â…¢only
(E) â… and â…¢
Prime DS
This topic has expert replies
- karthikpandian19
- Legendary Member
- Posts: 1665
- Joined: Thu Nov 03, 2011 7:04 pm
- Thanked: 165 times
- Followed by:70 members
GMAT/MBA Expert
- Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
(I) x = ykarthikpandian19 wrote:If y ≠3 and 3x/y is a prime integer greater than 2, which of the following must be true?
â… . x = y
â…¡. y = 1
â…¢. x and y are prime integers.
(A) None
(B) â… only
(C) â…¡only
(D) â…¢only
(E) â… and â…¢
If x = 5, y = 5, then 3x/y = 3 (a prime) greater than 2.
If x = 25, y = 15, then 3x/y = 5 (a prime number) greater than 2.
So, x = y is not always true.
(II) y = 1 is again not always true.
(III) x and y are prime integers is again not true because if we take x = 10, y = 6, then 3x/y = 5
So, again it is not true always.
The correct answer is A.
Last edited by Anurag@Gurome on Fri Dec 16, 2011 3:30 am, edited 1 time in total.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
- karthikpandian19
- Legendary Member
- Posts: 1665
- Joined: Thu Nov 03, 2011 7:04 pm
- Thanked: 165 times
- Followed by:70 members
In your proving portion, you had considered "I" y=3, but as per the statement y"not equal to" 3?????
Anurag@Gurome wrote:(I) x = ykarthikpandian19 wrote:If y ≠3 and 3x/y is a prime integer greater than 2, which of the following must be true?
â… . x = y
â…¡. y = 1
â…¢. x and y are prime integers.
(A) None
(B) â… only
(C) â…¡only
(D) â…¢only
(E) â… and â…¢
If x = 5, y = 5, then 3x/y = 3 (a prime) greater than 2.
If x = 7, y = 3, then 3x/y = 7 (a prime number) greater than 2.
So, x = y is not always true.
(II) y = 1 is again not always true.
(III) x and y are prime integers is again not true because if we take x = 10, y = 6, then 3x/y = 5
So, again it is not true always.
The correct answer is A.
-
- Senior | Next Rank: 100 Posts
- Posts: 49
- Joined: Thu Feb 17, 2011 1:36 am
- Thanked: 8 times
- Followed by:2 members
@ Anurag@Gurome:
Correct me if i am wrong:In your proof firstly you took y = 3 but in question its clearly given y is not 3.
Secondly you took it under x=y,and x=7,y=3?? if x= 7 and x= y how can y be 3.
I believe the answer is A.
Since x = y always results in 3x/y being 3 which is greater than 2 and prime integer.
B)y =1 leads to 3x which depends on value of x,hence not true.
C)X and Y being prime integers leads to 3x/y not being prime integer.
Thus A.
Correct me if i am wrong:In your proof firstly you took y = 3 but in question its clearly given y is not 3.
Secondly you took it under x=y,and x=7,y=3?? if x= 7 and x= y how can y be 3.
I believe the answer is A.
Since x = y always results in 3x/y being 3 which is greater than 2 and prime integer.
B)y =1 leads to 3x which depends on value of x,hence not true.
C)X and Y being prime integers leads to 3x/y not being prime integer.
Thus A.
GMAT/MBA Expert
- Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
My mistake, i have edited the previous reply. Thanks for pointing it out.ankush123251 wrote:@ Anurag@Gurome:
Correct me if i am wrong:In your proof firstly you took y = 3 but in question its clearly given y is not 3.
Secondly you took it under x=y,and x=7,y=3?? if x= 7 and x= y how can y be 3.
I believe the answer is A.
Since x = y always results in 3x/y being 3 which is greater than 2 and prime integer.
B)y =1 leads to 3x which depends on value of x,hence not true.
C)X and Y being prime integers leads to 3x/y not being prime integer.
Thus A.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
-
- Senior | Next Rank: 100 Posts
- Posts: 49
- Joined: Thu Feb 17, 2011 1:36 am
- Thanked: 8 times
- Followed by:2 members
GMAT/MBA Expert
- Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
Yes, that's right, it's none.ankush123251 wrote:Is the answer None?
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/