Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 23 May 2013, 00:03
Customize  |  Hide

Search
Register
New posts
Unanswered

If two of the four expressions

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
VP
VP
User avatar
Joined: 18 May 2008
Posts: 1305
Followers: 9

Kudos [?]: 57 [0], given: 0

GMAT Tests User
If two of the four expressions [#permalink] New post 13 Nov 2008, 03:24
Help!
Attachments

product.JPG
product.JPG [ 39.82 KiB | Viewed 416 times ]

Manager
Manager
Joined: 30 Sep 2008
Posts: 114
Followers: 1

Kudos [?]: 7 [0], given: 0

Re: GMATPREP-product [#permalink] New post 13 Nov 2008, 03:45
x^2 - (by)^2 = (x-by)(x+by)

The probability P1 to get (x-by) = 1/4 as only x-y satisfies
Once taking x-y out of the list, the probability P2 to get x + by is 2 out of 3 (x+y and x+5y)

P = P1 * P2 = 1/4 * 2/3 = 1/6
Senior Manager
Senior Manager
User avatar
Joined: 04 Aug 2008
Posts: 381
Followers: 3

Kudos [?]: 18 [0], given: 1

GMAT Tests User
Re: GMATPREP-product [#permalink] New post 13 Nov 2008, 07:22
to satisfy the condition x^2-y^2 we need to have this form (x-y)(x+y)

so... two expressions are in the form (x-y) and two (x+y)

so 2*2/4*3*2*1=4/24=1/6

this is a tricky one...
_________________

The one who flies is worthy. The one who is worthy flies. The one who doesn't fly isn't worthy

Manager
Manager
Joined: 23 Jul 2008
Posts: 207
Followers: 1

Kudos [?]: 18 [0], given: 0

GMAT Tests User
Re: GMATPREP-product [#permalink] New post 13 Nov 2008, 12:25
pretty straight forward

to get product of the nature of x^2 - (by)^2 we need to pick both (x+y) and (x-y) from a total of 4 expressions

probability= 2/4*1/3=1/6
Director
Director
Joined: 14 Aug 2007
Posts: 747
Followers: 6

Kudos [?]: 65 [0], given: 0

GMAT Tests User
Re: GMATPREP-product [#permalink] New post 13 Nov 2008, 20:13
1/4C2 = 1/6 ( 1 for choosing x+y, x-y)
Re: GMATPREP-product   [#permalink] 13 Nov 2008, 20:13
    Similar topics Author Replies Last post
Similar
Topics:
 New posts If two of the four expressions, x+y, x+5y, x-y and 5x-y are MBAlad 4 21 Feb 2006, 08:45
New posts GMATPrep - Four expressions suniluic 4 04 May 2007, 13:37
New posts If two of the four expressions x+y, x+5y, x-y and 5y-x are Dek 4 08 Jun 2007, 10:34
New posts EXPERTS_POSTS_IN_THIS_TOPIC If two of the four expressions x+y, x+5y, x-y, and 5x-y are GMATBLACKBELT 6 24 Oct 2007, 22:35
New posts If two of the four expressions x +y, x +5y, x -y and 5x -y marcodonzelli 2 09 Mar 2008, 02:23
Display posts from previous: Sort by

If two of the four expressions

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma

Search for:


cron

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

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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com