Find all School-related info fast with the new School-Specific MBA Forum

It is currently 16 Apr 2014, 05:32

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If x and y are positive, what's the value of x? 1. 200% of x

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1543
Followers: 4

Kudos [?]: 51 [0], given: 39

If x and y are positive, what's the value of x? 1. 200% of x [#permalink] New post 10 Aug 2009, 10:02
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

100% (04:26) correct 0% (00:00) wrong based on 1 sessions
If x and y are positive, what's the value of x?

1. 200% of x = 400% of y
2. xy is the square of a positive integer
Director
Director
User avatar
Joined: 01 Apr 2008
Posts: 911
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 10

Kudos [?]: 161 [0], given: 18

GMAT Tests User
Re: percents [#permalink] New post 10 Aug 2009, 10:20
yezz wrote:
If x and y are positive, what's the value of x?

1. 200% of x = 400% of y
2. xy is the square of a positive integer

I get E.

1) we don't have value of y,so insufficient.
2) xy can be 1,4,9,...
combining,
x/y = 2, now if x is a fraction y is also a fraction, in that case xy would not be a square of a positive integer, so x and y are integers.
I could not find any combination where x/y = 2 and xy is a square of a positive integer.

OA and OE pls
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1543
Followers: 4

Kudos [?]: 51 [0], given: 39

Re: percents [#permalink] New post 10 Aug 2009, 10:24
Economist wrote:
yezz wrote:
If x and y are positive, what's the value of x?

1. 200% of x = 400% of y
2. xy is the square of a positive integer

I get E.

1) we don't have value of y,so insufficient.
2) xy can be 1,4,9,...
combining,
x/y = 2, now if x is a fraction y is also a fraction, in that case xy would not be a square of a positive integer, so x and y are integers.
I could not find any combination where x/y = 2 and xy is a square of a positive integer.

OA and OE pls


will do after some discussion..ok
Intern
Intern
Joined: 29 Jun 2009
Posts: 15
Location: Dallas TX
Followers: 0

Kudos [?]: 3 [0], given: 0

Re: percents [#permalink] New post 10 Aug 2009, 11:07
E

I don't think there is any combination where x = 2y and xy is a perfect square.

xy = z^2
2y^2 = z^2
z = y . Sqrt2

and both z and y are integers. I don't know if there is any
Senior Manager
Senior Manager
User avatar
Joined: 20 Mar 2008
Posts: 457
Followers: 1

Kudos [?]: 54 [0], given: 5

GMAT Tests User
Re: percents [#permalink] New post 10 Aug 2009, 11:12
St. 1 : No values for x or y. So Insuff.

St. 2: XY can have multiple values. Insuff.

Combined: We know from St. 1, x = 2y, hence xy = 2y.y = 2y^2.

Now, if y = 2^-.5, then 2y^2 = 2. 1 / (2^.5)^2 = 1. (x & y can be fractions, but not xy.)

1 is a square of a positive integer, 1.

For no other value of y will this hold true. Hence, sufficient.

So, C for me.
Director
Director
User avatar
Joined: 01 Apr 2008
Posts: 911
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 10

Kudos [?]: 161 [0], given: 18

GMAT Tests User
Re: percents [#permalink] New post 10 Aug 2009, 11:20
Good one Jivana. So finally we got a possibility :) Thanks!
C.
SVP
SVP
User avatar
Joined: 05 Jul 2006
Posts: 1543
Followers: 4

Kudos [?]: 51 [0], given: 39

Re: percents [#permalink] New post 10 Aug 2009, 11:34
Econ... u wr right ....E


St1: x = 2y Infinite possibilities: INSUFF

St2: xy is a perfect square. Infinite possibilities: INSUFF

Together:
xy = 2x^2

2x^2 is a perfect square.
x = √8, y = 2* √8
x = √18 y = 2*√18
Infinitie possibilities: INSUFF
Director
Director
User avatar
Joined: 01 Apr 2008
Posts: 911
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 10

Kudos [?]: 161 [0], given: 18

GMAT Tests User
Re: percents [#permalink] New post 10 Aug 2009, 21:28
arghhhhhhh !!! Thanks for the clarification yezz :)
Re: percents   [#permalink] 10 Aug 2009, 21:28
    Similar topics Author Replies Last post
Similar
Topics:
New posts If x and y are positive, what's the value of x? 1. 200% of x GMATT73 2 05 Sep 2006, 09:30
New posts 4 If x and y are positive, what is the value of x y? (1) (x^2 carlson2010 3 10 Jun 2008, 12:33
New posts If x and y are positive integers, what is the value of x? linau1982 5 16 Oct 2008, 06:58
New posts 1 If x and y are positive, what is the value of x-y? 1) (X^2 - hardaway7 3 29 Dec 2008, 10:26
New posts Experts publish their posts in the topic If x and y are positive, what is the value of x-y? eybrj2 2 05 Apr 2012, 12:25
Display posts from previous: Sort by

If x and y are positive, what's the value of x? 1. 200% of x

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.