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

It is currently 31 Aug 2015, 17:50
GMAT Club Tests

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

What is the value of R? 1. R^R = R 2. (1/R)^R = R Can

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2760
Location: New York City
Followers: 9

Kudos [?]: 421 [0], given: 4

What is the value of R? 1. R^R = R 2. (1/R)^R = R Can [#permalink] New post 08 Nov 2007, 03:34
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?
Director
Director
User avatar
Joined: 03 Sep 2006
Posts: 884
Followers: 6

Kudos [?]: 337 [0], given: 33

GMAT ToolKit User
 [#permalink] New post 08 Nov 2007, 04:57
Statement (i) is not sufficient to tell the value of R, which can be 1 or -1. Thus insufficient.

Same in case of statement (ii), R can be 1 and also -1.

Thus answer should be "E".

What is OA?
Senior Manager
Senior Manager
User avatar
Joined: 01 Sep 2006
Posts: 301
Location: Phoenix, AZ, USA
Followers: 1

Kudos [?]: 15 [0], given: 0

Re: variable base to variable exponent [#permalink] New post 08 Nov 2007, 06:36
bmwhype2 wrote:
What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?


Using 1
R^R=R==> R^R-R=0==> R(R^(R-1) -1)=0==>
Either R =0
or R^ (R-1)-1=0==> R^(R-1)=1 i.e. R=1


Using 2

1/R^R=R==> 1=R^(R+1) either R=1 or R=-1

Togather R=1
Director
Director
User avatar
Joined: 03 Sep 2006
Posts: 884
Followers: 6

Kudos [?]: 337 [0], given: 33

GMAT ToolKit User
Re: variable base to variable exponent [#permalink] New post 08 Nov 2007, 06:44
Damager wrote:
bmwhype2 wrote:
What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?


Using 1
R^R=R==> R^R-R=0==> R(R^(R-1) -1)=0==>
Either R =0
or R^ (R-1)-1=0==> R^(R-1)=1 i.e. R=1


Using 2

1/R^R=R==> 1=R^(R+1) either R=1 or R=-1

Togather R=1



Why R=-1 is not possible for the statement (i)?
SVP
SVP
User avatar
Joined: 01 May 2006
Posts: 1798
Followers: 10

Kudos [?]: 108 [0], given: 0

 [#permalink] New post 08 Nov 2007, 07:34
(E) for me too :)

R=?

Stat1
We have : R^R = R

o If R=-1, then (-1)^(-1) = -1
o If R=1, then (1)^(1) = 1

INSUFF.

Stat2
(1/R)^R = R

o If R=-1, then (1/(-1))^(-1) = -1
o If R=1, then (1/(1))^(1) = 1

INSUFF.

Both (1) and (2)
We remain with 2 cases : R=1 or R=-1.

INSUFF.
Director
Director
User avatar
Joined: 13 Dec 2006
Posts: 520
Location: Indonesia
Followers: 6

Kudos [?]: 124 [0], given: 0

 [#permalink] New post 08 Nov 2007, 07:38
Answer is E

1. R^R = R is only possible when R is equal to either 1 or -1
2. (1/R)^R = R, here also the equation is true for both 1 an -1

As both are insufficient and together doesn make sense... hence answer is E
SVP
SVP
User avatar
Joined: 01 May 2006
Posts: 1798
Followers: 10

Kudos [?]: 108 [0], given: 0

Re: variable base to variable exponent [#permalink] New post 08 Nov 2007, 10:13
sportyrizwan wrote:
Damager wrote:
bmwhype2 wrote:
What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?


Using 1
R^R=R==> R^R-R=0==> R(R^(R-1) -1)=0==>
Either R =0
or R^ (R-1)-1=0==> R^(R-1)=1 i.e. R=1


Using 2

1/R^R=R==> 1=R^(R+1) either R=1 or R=-1

Togather R=1



I agree ...C it is


In statment 1, R=-1 works too :)... R^R = (-1)^(-1) = -1 = R....
Manager
Manager
avatar
Joined: 01 Nov 2007
Posts: 69
Followers: 1

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

 [#permalink] New post 10 Nov 2007, 11:32
I change my stand to E

thanks Fig
Senior Manager
Senior Manager
avatar
Joined: 06 Aug 2007
Posts: 368
Followers: 1

Kudos [?]: 25 [0], given: 0

Re: variable base to variable exponent [#permalink] New post 22 Nov 2007, 18:55
bmwhype2 wrote:
What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?


1 . Take R = 0, 1, or -1 all of them will work so not Sufficient.

2. Take R = 1 or -1 it will work so not sufficient..

Together also they dont give you one solution.

So E
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2760
Location: New York City
Followers: 9

Kudos [?]: 421 [0], given: 4

Re: variable base to variable exponent [#permalink] New post 22 Nov 2007, 18:56
spider wrote:
bmwhype2 wrote:
What is the value of R?
1. R^R = R
2. (1/R)^R = R

Can someone explain this in detail for me?


1 . Take R = 0, 1, or -1 all of them will work so not Sufficient.

2. Take R = 1 or -1 it will work so not sufficient..

Together also they dont give you one solution.

So E


0^0 is not valid in gmatland
Re: variable base to variable exponent   [#permalink] 22 Nov 2007, 18:56
Display posts from previous: Sort by

What is the value of R? 1. R^R = R 2. (1/R)^R = R Can

  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®.