It is currently 18 Oct 2017, 23:17

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

x and y are consecutive positive integers and: x > y ,

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Manager
Manager
avatar
Joined: 12 Feb 2008
Posts: 177

Kudos [?]: 46 [0], given: 0

x and y are consecutive positive integers and: x > y , [#permalink]

Show Tags

New post 29 Oct 2008, 07:41
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

x and y are consecutive positive integers and:
x > y , x^2 - 1 > y^2 - 4y + x - 1
Which of the following represents all the possible values of Y?


* y >=0
* y > 0
* y > 1
* y > 7
* y > 8

please provide detailed answer.

Kudos [?]: 46 [0], given: 0

SVP
SVP
User avatar
Joined: 29 Aug 2007
Posts: 2472

Kudos [?]: 843 [0], given: 19

Re: consecutive positive integers [#permalink]

Show Tags

New post 29 Oct 2008, 08:39
elmagnifico wrote:
x and y are consecutive positive integers and:
x > y , x^2 - 1 > y^2 - 4y + x - 1
Which of the following represents all the possible values of Y?


* y>=0
* y > 0
* y > 1
* y > 7
* y > 8

please provide detailed answer.


x^2 - 1 > y^2 - 4y + x - 1
x^2 - x > y^2 - 4y
x (x - 1) > y (y - 4)
since x and y are +ve consecutive integers, y = x - 1 or x = y + 1

(y+1) y > y (y - 4)
y + 1 > y - 4
y > (y - 5)

what value for y work in the above expression? anything but y should be a +ve. so y has to be at least 1 or y > 0.

But I am still missing a more succint way to solve this problem.
_________________

Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html
Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html
Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT

Kudos [?]: 843 [0], given: 19

SVP
SVP
User avatar
B
Joined: 05 Jul 2006
Posts: 1750

Kudos [?]: 430 [0], given: 49

GMAT ToolKit User
Re: consecutive positive integers [#permalink]

Show Tags

New post 29 Oct 2008, 09:45
[quote="elmagnifico"]x and y are consecutive positive integers and:
x > y , x^2 - 1 > y^2 - 4y + x - 1

Which of the following represents all the possible values of Y?


y >=0
y > 0
y > 1
y > 7
y > 8


(x-1)(x+1)-x > (y-1)(y+1)-4y

x is = (y-1)) as x>y AND THEY ARE CONSECS

thus

(y-2)(y)> (y-1)(y+1)-4y

5*3>4*6 - 4*5.....true

0> -1*1 true, BUT GIVEN IS y+VE THUS

I will go with Y>0

Kudos [?]: 430 [0], given: 49

VP
VP
User avatar
Joined: 30 Jun 2008
Posts: 1034

Kudos [?]: 705 [0], given: 1

Re: consecutive positive integers [#permalink]

Show Tags

New post 29 Oct 2008, 10:01
check this thread http://gmatclub.com/forum/post532313.html#p532313
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Kudos [?]: 705 [0], given: 1

Current Student
avatar
Joined: 28 Dec 2004
Posts: 3351

Kudos [?]: 319 [0], given: 2

Location: New York City
Schools: Wharton'11 HBS'12
Re: consecutive positive integers [#permalink]

Show Tags

New post 29 Oct 2008, 10:14
elmagnifico wrote:
x and y are consecutive positive integers and:
x > y , x^2 - 1 > y^2 - 4y + x - 1
Which of the following represents all the possible values of Y?
* y >=0
* y > 0
* y > 1
* y > 7
* y > 8
please provide detailed answer.


lets see x>y then x=y+1

x^2 - 1= (x-1)(x+1) => (y+1-1)(Y+1+1)=y(Y+2) or y^2 +2y>y^2-4y+y+1-1

5y>0 which means y>0 , however, the stems says x and y are consecutive POSITIVE intgers..therefore y>0 or y=1 ..or 2..

Kudos [?]: 319 [0], given: 2

Re: consecutive positive integers   [#permalink] 29 Oct 2008, 10:14
Display posts from previous: Sort by

x and y are consecutive positive integers and: x > y ,

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.