It is currently 24 Mar 2018, 18:28

### 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

# For any numbers x#y = xy - x - y . If x#y = 1 , which of the

Author Message
Current Student
Joined: 11 May 2008
Posts: 552
For any numbers x#y = xy - x - y . If x#y = 1 , which of the [#permalink]

### Show Tags

25 Aug 2008, 03:38
1
This post was
BOOKMARKED
For any numbers x#y = xy - x - y . If x#y = 1 , which of the following cannot be the value of y ?

* -2
* -1
* 0
* 1
* 2

why is A not the soln??

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Manager
Joined: 15 Jul 2008
Posts: 205

### Show Tags

25 Aug 2008, 04:16
arjtryarjtry wrote:
For any numbers x#y = xy - x - y . If x#y = 1 , which of the following cannot be the value of y ?

* -2
* -1
* 0
* 1
* 2

why is A not the soln??

the question does not say that x, and y are integers. So y=-2 is possible. Here what you need to do is put xy-x-y=1 and try out different values of y.
with y=-2, u get x=1/3. So y can be -2.

Answer is 1. if y=1, then you get -1=1 which is not possible.
Director
Joined: 12 Jul 2008
Posts: 513
Schools: Wharton

### Show Tags

25 Aug 2008, 04:23
arjtryarjtry wrote:
For any numbers x#y = xy - x - y . If x#y = 1 , which of the following cannot be the value of y ?

* -2
* -1
* 0
* 1
* 2

why is A not the soln??

1 = xy - x - y
1 = x(y-1) - y
y + 1 = x(y-1)

Thus, y cannot be 1.
If y = 1, y+1 = 2 and x(y-1) = 0
Intern
Joined: 16 Feb 2006
Posts: 30
Location: ZURICH

### Show Tags

25 Aug 2008, 06:32
For any numbers x#y = xy - x - y . If x#y = 1 , which of the following cannot be the value of y ?

* -2
* -1
* 0
* 1
* 2

Here we have x#y = 1
which means
xy - x - y = 1
or, xy - x = 1 + y
or, x(y-1) = 1 + y
or, x = (1 + y)/(y - 1)

x will be undefined if y - 1 = 0
or y = 1

and if we substitute y = -2
we get x = 1/3

and x#y = 1

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________

TRY N TRY UNTIL U SUCCEED

Re: variable...   [#permalink] 25 Aug 2008, 06:32
Display posts from previous: Sort by

# For any numbers x#y = xy - x - y . If x#y = 1 , which of the

Moderator: chetan2u

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.