M9 #21 : Retired Discussions [Locked]
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 21 Jan 2017, 02:44

### 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

# M9 #21

Author Message
Director
Joined: 11 Jun 2007
Posts: 931
Followers: 1

Kudos [?]: 175 [0], given: 0

### Show Tags

20 Sep 2009, 23:51
If the operation $$#$$ satisfies $$X#Y = \frac{1}{X#Y}$$ for any non-zero number $$X$$ and $$Y$$ , which of the following can be $$#$$ ?

1. $$X#Y = \frac{1}{XY}$$
2. $$X#Y = \frac{X}{Y}$$
3. $$X#Y = XY$$

I understood the answer how X#Y can only be 1 or -1 but can someone explain why 1, 2, or 3 could not equal 1 or -1. Thanks.
Manager
Joined: 08 Nov 2005
Posts: 182
Followers: 2

Kudos [?]: 19 [1] , given: 10

### Show Tags

28 Sep 2009, 11:15
1
KUDOS
Can you post the entire question.

1. 1/XY=XY
2. X/Y = Y/X
3. XY = 1/XY (same as No. 1)

These are the 3 condition. Now for condition 2. X & Y does not have to be just 1 or -1 it can be any integer as long as X=Y
for example X=2 Y=2 -> X/Y is Y/X

but for 1 & 3 X & Y can be only 1 or -1.
you should also take fraction since it does not say integer.

Manager
Joined: 23 Jan 2013
Posts: 174
Concentration: Technology, Other
Schools: Haas
GMAT Date: 01-14-2015
WE: Information Technology (Computer Software)
Followers: 3

Kudos [?]: 44 [0], given: 41

### Show Tags

01 Jun 2014, 04:24
If the operation # satisfies X # Y = 1/(X # Y) for any non-zero number X and Y, which of the following can be #?

1. X # Y = 1/XY
2. X # Y = X/Y
3. X # Y = XY

None
1 only
2 only
1 and 2 only
1 and 3 only

I still cannot figure this question out , can anyone help me out here ?
Math Expert
Joined: 02 Sep 2009
Posts: 36585
Followers: 7088

Kudos [?]: 93303 [0], given: 10557

### Show Tags

01 Jun 2014, 04:37
shelrod007 wrote:
If the operation # satisfies X # Y = 1/(X # Y) for any non-zero number X and Y, which of the following can be #?

1. X # Y = 1/XY
2. X # Y = X/Y
3. X # Y = XY

None
1 only
2 only
1 and 2 only
1 and 3 only

I still cannot figure this question out , can anyone help me out here ?

This question was removed from data base. So, don't worry about it.
_________________
Re: M9 #21   [#permalink] 01 Jun 2014, 04:37
Similar topics Replies Last post
Similar
Topics:
15 m02 #21 28 14 Nov 2008, 12:33
6 M12 # 21 19 13 Nov 2008, 12:47
V06 Number 21 4 10 Oct 2008, 03:47
17 m9 q34 38 18 Jul 2008, 01:44
32 M21 #28 26 23 Aug 2008, 22:50
Display posts from previous: Sort by

# M9 #21

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO 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®.