NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 03:25 It is currently 25 Apr 2024, 03:25
Decision Tracker
My Rewards
New posts
New comers' posts

Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

If x and y are prime numbers, what is the value of |x-y|?

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
banksy
Manager
Manager
Joined: 10 Feb 2011
Posts: 86
Own Kudos [?]: 1627 [35]
Given Kudos: 10
Send PM
If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   Updated on: 07 Sep 2013, 06:02
6
Kudos
29
Bookmarks
00:00
A
B
C
D
E

Difficulty:

85% (hard)

Question Stats:

34% (01:20) correct 66% (01:16) wrong based on 431 sessions
Hide Show timer Statistics
If x and y are prime numbers, what is the value of |x-y|?

(1) x + y is a prime number
(2) Both x and y are less than 5

M10-29

Experience a GMAT Club Test Questions
Yes, you've landed on a GMAT Club Tests question
Craving more? Unlock our full suite of GMAT Club Tests here
Want to experience more? Get a taste of our tests with our free trial today
Rise to the challenge with GMAT Club Tests. Happy practicing!
GMAT Club Tests Check Our Products Try Free Tests
ShowHide Answer
Official Answer
C

Originally posted by banksy on 15 Mar 2011, 16:36.
Last edited by Bunuel on 07 Sep 2013, 06:02, edited 1 time in total.
Renamed the topic, edited the question and the OA.
Most Helpful Reply
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92912
Own Kudos [?]: 618897 [7]
Given Kudos: 81595
Send PM
CAT Tests Forum Quiz Mode
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   07 Sep 2013, 06:05
4
Kudos
3
Bookmarks
Expert Reply
ygdrasil24 wrote:
Spidy001 wrote:
Answer should be C for this one.

Question doesnt say that A and B are different.

1. Not sufficient

2,5 diff 3
2,11 diff 9

2. Not sufficient

2,2 diff 0
3,3 difff 0
2 3 diff 1

together we know that a and b has to different , because a+b is prime. so sufficient.

Answer C.


If A=2, B=2 , |A-B| = 0
If A=2/3 , B=2/3, |A-B|= 1

So how is answer is B ? Should be C ?


This is GMAT Club question and the answer is C.

If x and y are prime numbers, what is the value of |x-y|?

(1) x + y is a prime number. Clearly insufficient, consider x=3, y=2 and x=5, y=2.

(2) Both x and y are less than 5. Also insufficient, consider x=3, y=2 and x=3, y=3. Notice that on the GMAT, unless it is explicitly stated otherwise, different variables CAN represent the same number. So, x=y is a valid scenario.

(1)+(2) Either x=3 and y=2 or vise versa. In any case |x-y|=1. Sufficient.

Answer: C.

P.S. Unless it is explicitly stated otherwise, different variables CAN represent the same number. So, x=y is a valid scenario.
General Discussion
User avatar
B
subhashghosh
Retired Moderator
Joined: 16 Nov 2010
Posts: 909
Own Kudos [?]: 1173 [1]
Given Kudos: 43
Location: United States (IN)
Concentration: Strategy, Technology
Send PM
Reviews Badge
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   15 Mar 2011, 20:25
1
Kudos
From (1) we have, one of A or B is 2, and the other one can be 3, 5, 11 etc., so (1) is not enough.

From (2), the only 2 prime numbers less than 5 are 2 and 3, so (2) is sufficient.

Hence the answer is B.
User avatar
fluke
Retired Moderator
Joined: 20 Dec 2010
Posts: 1114
Own Kudos [?]: 4702 [4]
Given Kudos: 376
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   16 Mar 2011, 03:59
4
Kudos
Q: |A-B|?

1. A=2, B=5; A+B=7; |A-B|=3
A=2, B=3; A+B=5; |A-B|=1
NS

2. A=2,B=2; |A-B|=0
A=2,B=3; |A-B|=1
A=3,B=2; |A-B|=1
A=3,B=3; |A-B|=0
NS

Combining 1 and 2;
A=2,B=3; A+B=5; |A-B|=1
A=3,B=2; A+B=5; |A-B|=1

Sufficient.

Ans: "C"
User avatar
vivesomnium
Manager
Manager
Joined: 09 Feb 2011
Posts: 175
Own Kudos [?]: 459 [0]
Given Kudos: 13
Concentration: General Management, Social Entrepreneurship
Schools: HBS '14 (A)
GMAT 1: 770 Q50 V47
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   16 Mar 2011, 04:08
statement 1: A + B is a prime integer- if sum of two prime integers is prime, one of them has to be 2( Prime nos. are all odd, except 2, and odd +odd is even, so to make A + B, at least one has to be even. only even prime is 2) However, there is no way to find the value of other prime, it can be any prime upto infininty, so a single value of |A-B| cant be established. Hence, insufficient.
2. Only integers less than 5 which are prime are 2 and 3. Absolute value of difference therefore has only one possible value (i.e.1)
Hence sufficient.
Answer : B
User avatar
Eden
Intern
Intern
Joined: 06 Apr 2010
Posts: 48
Own Kudos [?]: 104 [0]
Given Kudos: 2
Send PM
GMAT ToolKit User
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   20 Mar 2011, 11:11
1. (GC) A and B are prime integers. What is |A - B|?
(1) A + B is a prime integer
(2) Both A and B are less than 5

my solution:
(1) A+B is a prime integer
One of the prime number is 2 and the other could be any prime number such that A+B is also a prime number (for ex: 3,5,7,11 etc). Therefore |A-B| could be any value => not sufficient
(2) Both A and B are less than 5
A and B could be 2 or 3, and A and B could be the same prime number . Therefore |A+B| could be 0 or 1. => not sufficient
(1 and 2)
A and B are 2 different prime numbers less that 5 (that means 2 and 3) => sufficient
User avatar
Spidy001
Senior Manager
Senior Manager
Joined: 01 Feb 2011
Posts: 309
Own Kudos [?]: 324 [2]
Given Kudos: 42
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   20 Mar 2011, 11:29
1
Kudos
1
Bookmarks
Answer should be C for this one.

Question doesnt say that A and B are different.

1. Not sufficient

2,5 diff 3
2,11 diff 9

2. Not sufficient

2,2 diff 0
3,3 difff 0
2 3 diff 1

together we know that a and b has to different , because a+b is prime. so sufficient.

Answer C.
User avatar
ygdrasil24
Manager
Manager
Joined: 07 Apr 2012
Posts: 71
Own Kudos [?]: 25 [0]
Given Kudos: 45
Location: United States
Concentration: Entrepreneurship, Operations
Schools: ISB '15
GMAT 1: 590 Q48 V23
GPA: 3.9
WE:Operations (Manufacturing)
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   07 Sep 2013, 02:16
Spidy001 wrote:
Answer should be C for this one.

Question doesnt say that A and B are different.

1. Not sufficient

2,5 diff 3
2,11 diff 9

2. Not sufficient

2,2 diff 0
3,3 difff 0
2 3 diff 1

together we know that a and b has to different , because a+b is prime. so sufficient.

Answer C.


If A=2, B=2 , |A-B| = 0
If A=2/3 , B=2/3, |A-B|= 1

So how is answer is B ? Should be C ?
User avatar
Chiranjeevee
Intern
Intern
Joined: 28 Jan 2013
Posts: 23
Own Kudos [?]: 40 [0]
Given Kudos: 20
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   11 Oct 2013, 12:46
jlgdr wrote:
A and B are prime integers. What is |A - B|?

(1) A + B is a prime integer
(2) Both A and B are less than 5


From 1. The value of A,B can be anything 2,3 or 2,5 or 2,17 so on.... Adding A+B we get a prime number with different values of |A-B|. Not sufficient.
From 2. Value of A,B must be 2,3 or 3,2 mod of their difference will always be 1. sufficient
User avatar
B
srinidhi mishra
Intern
Intern
Joined: 01 May 2017
Posts: 11
Own Kudos [?]: 1 [0]
Given Kudos: 8
Concentration: General Management, Leadership
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   07 Jun 2017, 11:40
If x and y are prime numbers, what is the value of |x-y|?

(1) x + y is a prime number
(2) Both x and y are less than 5

1-x+y =PN 2 & 3, 2& 5, 2& 11, 2&17 etc
x,y<5 i.e. 2&3
B alone answers the question
How come OA is C ?
avatar
B
Shiwangvictory123
Intern
Intern
Joined: 09 May 2020
Posts: 6
Own Kudos [?]: 2 [0]
Given Kudos: 0
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   10 Sep 2020, 21:17
if x and y are prime number than combinations can be 2 and 3, 3 and 5

1: x+y is a prime number
it is possible in many cases
a) x=2,y=3
b) x=2,y=7
Not sufficient
2: Not sufficient
Combining both we see only one case which is x=2 and y=3
So Answer is C
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 32665
Own Kudos [?]: 821 [0]
Given Kudos: 0
Send PM
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink] New post   04 Jun 2023, 20:40
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
gmatclubot
Re: If x and y are prime numbers, what is the value of |x-y|? [#permalink]
04 Jun 2023, 20:40
Moderator:
Bunuel
Math Expert
92912 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions