GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 20 Aug 2018, 09:41

### 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

# If k does not equal 0,1, or -1 is 1/k>0? (And why?) 1)

Author Message
Intern
Joined: 23 May 2008
Posts: 47
If k does not equal 0,1, or -1 is 1/k>0? (And why?) 1)  [#permalink]

### Show Tags

05 Dec 2008, 20:21
If k does not equal 0,1, or -1 is 1/k>0? (And why?)

1) 1/(k-1)>0

2) 1/(k+1)>0

(GMAT practice test http://www.mba.com)

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Manager
Joined: 27 May 2008
Posts: 192

### Show Tags

05 Dec 2008, 20:44
A

1) 1/(k-1)>0

k-1 < 0 ; k<1 so 1/k>1 SUFF

2) 1/(k+1)>0

k+1 <0 k< -1 ; 1/k >-1 IN SUFF
Intern
Joined: 05 Dec 2008
Posts: 20

### Show Tags

06 Dec 2008, 10:54
1
Another way (possibly easier) to read the question "is 1/k > 0?" is "is k positive?"
That's what the question is really asking since the only way for 1/k to be greater than zero (i.e., positive) is for b to be positive.
We can also read our data this way. So now we get a slightly new question:
If k does not equal 0,1, or -1 is k positive?
(1) 1/(k-1) is positive
(2) 1/(k+1)is positive

(1) if 1/k-1 is positive then it must be the case that k-1 is positive.
If k-1 is positive, then k must be greater than 1 (i.e., k>1)
Is this enough information to determine whether k is positive? You bet.

(2) if 1/k+1 is positive then it must be the case that k+1 is positive.
If k+1 is positive, then k must be greater than -1 (i.e., k>-1)
Is this enough information to determine whether k is positive?
No. k could equal -0.5 or it could equal 3

Intern
Joined: 23 May 2008
Posts: 47

### Show Tags

08 Dec 2008, 11:51
Thanks for both those explanations. That helps a lot. It is good to see how to figure it in a few different ways.

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: Data Sufficiency &nbs [#permalink] 08 Dec 2008, 11:51
Display posts from previous: Sort by

# If k does not equal 0,1, or -1 is 1/k>0? (And why?) 1)

Moderator: chetan2u

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.