Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 24 May 2017, 05:28

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Official Guide Quantitative Problem

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 03 Jul 2007
Posts: 1
Followers: 0

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

Official Guide Quantitative Problem [#permalink]

### Show Tags

12 Jul 2007, 23:15
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

This is Question 111 (pg 157) from OG Quantitative Review, a DS problem.

If x is a positive integer and w is a negative integer, what is the value of xw?

1) x^w = 1/2
2) w = -1

My answer:
1) Since value of w is not known, this eq is INSUFFICIENT.
2) Since x is unknown, this eq is INSUFFICIENT.

However, when you plug in w = -1 in eq (1), the answer is obtained. I felt that both statements together are sufficient.

The official answer: statement 1) alone is sufficient, but 2) is insufficient.

Where am I doing wrong??
GMAT Instructor
Joined: 04 Jul 2006
Posts: 1263
Location: Madrid
Followers: 29

Kudos [?]: 307 [0], given: 0

Re: Official Guide Quantitative Problem [#permalink]

### Show Tags

12 Jul 2007, 23:39
tmani136 wrote:
This is Question 111 (pg 157) from OG Quantitative Review, a DS problem.

If x is a positive integer and w is a negative integer, what is the value of xw?

1) x^w = 1/2
2) w = -1

My answer:
1) Since value of w is not known, this eq is INSUFFICIENT.
2) Since x is unknown, this eq is INSUFFICIENT.

However, when you plug in w = -1 in eq (1), the answer is obtained. I felt that both statements together are sufficient.

The official answer: statement 1) alone is sufficient, but 2) is insufficient.

Where am I doing wrong??

If you think that (1) is insufficient, show that it is so by finding two different answers to the question that are consistent with (1)
Senior Manager
Joined: 04 Jun 2007
Posts: 345
Followers: 1

Kudos [?]: 30 [0], given: 0

Re: Official Guide Quantitative Problem [#permalink]

### Show Tags

12 Jul 2007, 23:47
tmani136 wrote:
This is Question 111 (pg 157) from OG Quantitative Review, a DS problem.

If x is a positive integer and w is a negative integer, what is the value of xw?

1) x^w = 1/2
2) w = -1

My answer:
1) Since value of w is not known, this eq is INSUFFICIENT.
2) Since x is unknown, this eq is INSUFFICIENT.

However, when you plug in w = -1 in eq (1), the answer is obtained. I felt that both statements together are sufficient.

The official answer: statement 1) alone is sufficient, but 2) is insufficient.

Where am I doing wrong??

We know x>0 and w<0.
From stmt 1: x^w = 1/2 = 2^(-1)
x=2, w=-1. Sufficient.

Stmt 2: Insufficient. x can be any value.
Director
Joined: 16 May 2007
Posts: 548
Followers: 2

Kudos [?]: 66 [0], given: 0

### Show Tags

13 Jul 2007, 09:23
only 2^-1 satisfies stmt 1. Sometimes it is preferred to plug in some kind of numbers to test the statement. This helps in most of the cases, specially with DS number properties. Make sure, to consider all types of numbers unless specified
Director
Joined: 30 Nov 2006
Posts: 591
Location: Kuwait
Followers: 15

Kudos [?]: 290 [0], given: 0

### Show Tags

13 Jul 2007, 13:57
If x is a positive integer and w is a negative integer, what is the value of xw?

1) x^w = 1/2
2) w = -1

It's either A, C, or E

Obviously once we know w=-1, then x^-1 = 1/x = 1/2 and thus x = 2 and xw = -2

So, it's either A or C

Last step,

x^w = 1/2 , since both x and y are integers, I believe there is only one solution for this equation
it really comes to 1/x^w , where w becomes a positive integer here

MY ANSWER: A
13 Jul 2007, 13:57
Display posts from previous: Sort by

# Official Guide Quantitative Problem

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.