It is currently 19 Nov 2017, 01:52

### 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

# number theory good question

Author Message
Manager
Status: ==GMAT Ninja==
Joined: 08 Jan 2011
Posts: 241

Kudos [?]: 95 [0], given: 46

Schools: ISB, IIMA ,SP Jain , XLRI
WE 1: Aditya Birla Group (sales)
WE 2: Saint Gobain Group (sales)

### Show Tags

27 Mar 2011, 00:04
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

### HideShow timer Statistics

If x and y are positive integers and (\sqrt{x})^y=y , then x-y could equal which of the following?

A -2
B -1
C 1
D 2
E 4

OA
[Reveal] Spoiler:
A

can anyone provide a way to get the answer through theory

_________________

WarLocK
_____________________________________________________________________________
The War is oNNNNNNNNNNNNN for 720+
see my Test exp here http://gmatclub.com/forum/my-test-experience-111610.html
do not hesitate me giving kudos if you like my post.

Kudos [?]: 95 [0], given: 46

Director
Status: Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing.
Affiliations: University of Chicago Booth School of Business
Joined: 03 Feb 2011
Posts: 871

Kudos [?]: 399 [0], given: 123

Re: number theory good question [#permalink]

### Show Tags

27 Mar 2011, 00:19
Yeah it is. 4^2= 2^4 Hence x- y = 2-4 =-2. This is intuitive.

Now lets look at algebra.

The stem can be written in this form

x^(y/2) = y
Squaring both sides

x^y =y^2

There are two possibilities. 2^2 = 2^2. Hence x-y = 0 or 2^4= 4^2 Hence x -y = 2-4 = -2.

Warlock007 wrote:
If x and y are positive integers and (\sqrt{x})^y=y , then x-y could equal which of the following?

A -2
B -1
C 1
D 2
E 4

OA
[Reveal] Spoiler:
A

can anyone provide a way to get the answer through theory

Kudos [?]: 399 [0], given: 123

Re: number theory good question   [#permalink] 27 Mar 2011, 00:19
Display posts from previous: Sort by