It is currently 13 Dec 2017, 18:49

# Decision(s) Day!:

CHAT Rooms | Ross R1 | Kellogg R1 | Darden R1 | Tepper R1

### 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 xy > 0, does (x – 1)(y – 1) = 1? (1) x + y = xy (2) x = y

Author Message
TAGS:

### Hide Tags

Intern
Joined: 20 Feb 2012
Posts: 42

Kudos [?]: 503 [0], given: 6

If xy > 0, does (x – 1)(y – 1) = 1? (1) x + y = xy (2) x = y [#permalink]

### Show Tags

23 Feb 2012, 23:33
2
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

76% (01:09) correct 24% (01:15) wrong based on 96 sessions

### HideShow timer Statistics

If xy > 0, does (x – 1)(y – 1) = 1?

(1) x + y = xy

(2) x = y
[Reveal] Spoiler: OA

Kudos [?]: 503 [0], given: 6

Math Expert
Joined: 02 Sep 2009
Posts: 42583

Kudos [?]: 135550 [1], given: 12697

Re: does (x – 1)(y – 1) = 1? [#permalink]

### Show Tags

23 Feb 2012, 23:38
1
KUDOS
Expert's post
BANON wrote:
If xy > 0, does (x – 1)(y – 1) = 1?

(1) x + y = xy

(2) x = y

If $$xy>0$$ does $$(x-1)(y-1)=1$$?

Question: is $$(x-1)(y-1)=1$$? --> is $$xy-x-y+1=1$$? is $$x+y=xy$$?

(1) $$x+y=xy$$ --> directly gives us the answer YES. Sufficient.

(2) $$x=y$$ --> question becomes: is $$x+x=x^2$$? --> is $$x(x-2)=0$$? --> is $$x=0$$ or $$x=2$$? --> since given that $$xy>0$$, then $$x\neq{0}$$, so the question becomes is $$x=2$$? We don't know that, hence this statement is not sufficient.

Hope it's clear.
_________________

Kudos [?]: 135550 [1], given: 12697

Intern
Joined: 20 Feb 2012
Posts: 42

Kudos [?]: 503 [0], given: 6

Re: does (x – 1)(y – 1) = 1? [#permalink]

### Show Tags

24 Feb 2012, 00:03
thank u BUNUEL for ur instant reply's

after ur explanation's they all seem like sub par questions.

Kudos [?]: 503 [0], given: 6

Non-Human User
Joined: 09 Sep 2013
Posts: 14870

Kudos [?]: 287 [0], given: 0

Re: If xy > 0, does (x – 1)(y – 1) = 1? (1) x + y = xy (2) x = y [#permalink]

### Show Tags

10 Nov 2016, 11:13
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.
_________________

Kudos [?]: 287 [0], given: 0

Re: If xy > 0, does (x – 1)(y – 1) = 1? (1) x + y = xy (2) x = y   [#permalink] 10 Nov 2016, 11:13
Display posts from previous: Sort by