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

 It is currently 05 May 2015, 16:46

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

Author Message
TAGS:
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

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

Difficulty:

(N/A)

Question Stats:

100% (04:26) correct 0% (00:00) wrong based on 0 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
Joined: 01 Apr 2008
Posts: 906
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 18

Kudos [?]: 305 [0], given: 18

Re: percents [#permalink]  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
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

Re: percents [#permalink]  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
Joined: 29 Jun 2009
Posts: 15
Location: Dallas TX
Followers: 0

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

Re: percents [#permalink]  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
Joined: 20 Mar 2008
Posts: 454
Followers: 1

Kudos [?]: 73 [0], given: 5

Re: percents [#permalink]  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
Joined: 01 Apr 2008
Posts: 906
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 18

Kudos [?]: 305 [0], given: 18

Re: percents [#permalink]  10 Aug 2009, 11:20
Good one Jivana. So finally we got a possibility Thanks!
C.
SVP
Joined: 05 Jul 2006
Posts: 1519
Followers: 5

Kudos [?]: 115 [0], given: 39

Re: percents [#permalink]  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
Joined: 01 Apr 2008
Posts: 906
Schools: IIM Lucknow (IPMX) - Class of 2014
Followers: 18

Kudos [?]: 305 [0], given: 18

Re: percents [#permalink]  10 Aug 2009, 21:28
arghhhhhhh !!! Thanks for the clarification yezz
Re: percents   [#permalink] 10 Aug 2009, 21:28
Similar topics Replies Last post
Similar
Topics:
2 If x is a positive integer and x^y=1, what is the value of x? 3 29 Dec 2014, 03:59
If x and y are positive, what is the value of x-y? 2 05 Apr 2012, 12:25
1 If x and y are positive, what is the value of x-y? 1) (X^2 - 3 29 Dec 2008, 10:26
4 If x and y are positive, what is the value of x y? (1) (x^2 3 10 Jun 2008, 12:33
If x and y are positive, what's the value of x? 1. 200% of x 2 05 Sep 2006, 09:30
Display posts from previous: Sort by