Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 28 May 2017, 06:40

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# if x and y are prime, is xy odd ? 1... x - y is even.

Author Message
Manager
Joined: 10 Jul 2006
Posts: 56
Followers: 1

Kudos [?]: 0 [0], given: 0

if x and y are prime, is xy odd ? 1... x - y is even. [#permalink]

### Show Tags

12 Nov 2006, 09:39
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

if x and y are prime, is xy odd ?

1... x − y is even.
2... x / y is not an integer.

Ο only statement 1 is sufficient to answer the question.
Ο only statement 2 is sufficient to answer the question.
Ο neither statement is sufficient, but together, they are.
Ο statement 1 is very sufficient...and so is statement 2.
Ο no can do.
Senior Manager
Joined: 23 Jun 2006
Posts: 387
Followers: 1

Kudos [?]: 322 [0], given: 0

### Show Tags

12 Nov 2006, 11:13

A is not suff. for x=y=2 (st1) holds, and xy is even (for all other options it is indeed odd).

st2 tells us x and y are different.
Manager
Joined: 03 Jul 2005
Posts: 192
Location: City
Followers: 1

Kudos [?]: 10 [0], given: 0

### Show Tags

12 Nov 2006, 11:28
if x and y are prime, is xy odd ?

1... x − y is even.
2... x / y is not an integer.

Ο only statement 1 is sufficient to answer the question.
Ο only statement 2 is sufficient to answer the question.
Ο neither statement is sufficient, but together, they are.
Ο statement 1 is very sufficient...and so is statement 2.
Ο no can do.

1) We know that X and Y are prime and there is only 1 even prime. For X-Y to be even both X and Y must be ODD (Cannot have ODD - EVEN to equal EVEN). This means XY will always be ODD. SUFF

2) Only tells us that Y does not go into X or that X < Y but does not tell us anything that will help in answering this questions.

Manager
Joined: 03 Jul 2005
Posts: 192
Location: City
Followers: 1

Kudos [?]: 10 [0], given: 0

### Show Tags

12 Nov 2006, 11:56
Yes thinking about it x and y can be 2 since it does not say they are different.

If this is the case, then I would go for C, since statement B tells us that the integers are different.
SVP
Joined: 05 Jul 2006
Posts: 1747
Followers: 6

Kudos [?]: 358 [0], given: 49

### Show Tags

12 Nov 2006, 13:12
if x and y are prime, is xy odd ?

1... x − y is even.
2... x / y is not an integer.

for xy to be odd thus all we need to proof is x,y not = 2

x-y is even

thus both are odd OR BOTH ARE TWO ........INSUFF

x/y is not an intiger

either ways any prime is not devisible except by itself and one so deviding any two primes will always yield a non integer ( this includes 2 too)...insuff

BOTH TOGETHER

THEY CANT BE EQUALL THUS MY ANSWER IS C
VP
Joined: 28 Mar 2006
Posts: 1372
Followers: 2

Kudos [?]: 33 [0], given: 0

### Show Tags

13 Nov 2006, 05:47
WinIT wrote:
if x and y are prime, is xy odd ?

1... x − y is even.
2... x / y is not an integer.

Ο only statement 1 is sufficient to answer the question.
Ο only statement 2 is sufficient to answer the question.
Ο neither statement is sufficient, but together, they are.
Ο statement 1 is very sufficient...and so is statement 2.
Ο no can do.

I will take E

1) say x=5 y=3 product is even though their diff is even
say x=7 y=3 product is odd though their diff is even
So A not suff

2) x/y not int.

say x=5 y=3 so 5/3 is not an int

so is 7/3 as above

so E should be it
Current Student
Joined: 28 Dec 2004
Posts: 3361
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 16

Kudos [?]: 297 [0], given: 2

### Show Tags

13 Nov 2006, 18:38
C it is..we dont know if X and Y are distinct..
GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5045
Location: Singapore
Followers: 31

Kudos [?]: 376 [0], given: 0

### Show Tags

13 Nov 2006, 18:41
St1:
We know both x and y must be odd primes. So xy is odd. Sufficient.

St2:
Insufficient. 2/7, 3/5 are all non-integers but the first pair (2 and 7) will yield an even product while the second pair (3 and 5) will yield an odd product.

Ans A
Current Student
Joined: 28 Dec 2004
Posts: 3361
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 16

Kudos [?]: 297 [0], given: 2

### Show Tags

13 Nov 2006, 20:50
what if x=2 y=2

x-y=0 which is an even number...

2*2=4 which is even...

ywilfred wrote:
St1:
We know both x and y must be odd primes. So xy is odd. Sufficient.

St2:
Insufficient. 2/7, 3/5 are all non-integers but the first pair (2 and 7) will yield an even product while the second pair (3 and 5) will yield an odd product.

Ans A
Manager
Joined: 29 Aug 2006
Posts: 156
Followers: 1

Kudos [?]: 6 [0], given: 0

### Show Tags

13 Nov 2006, 20:58
Fell for this!
Intern
Joined: 06 Sep 2006
Posts: 27
Followers: 0

Kudos [?]: 1 [0], given: 0

### Show Tags

13 Nov 2006, 21:19
Should be A....

0 is not an even number.....
Senior Manager
Joined: 01 Oct 2006
Posts: 496
Followers: 1

Kudos [?]: 35 [0], given: 0

### Show Tags

14 Nov 2006, 01:59
O is a even number
Manager
Joined: 10 Jul 2006
Posts: 56
Followers: 1

Kudos [?]: 0 [0], given: 0

### Show Tags

14 Nov 2006, 17:54
OA is C. Thank you all for the explanation.
Senior Manager
Joined: 13 Sep 2006
Posts: 279
Location: New York
Followers: 1

Kudos [?]: 19 [0], given: 0

### Show Tags

14 Nov 2006, 19:16
Nice explanation Yezz.

I fell for that one...
_________________

"Never let the fear of striking out get in your wayâ€

14 Nov 2006, 19:16
Display posts from previous: Sort by