If k is not 0,1,-1, is 1/k >0? 1. 1/k-1 >0 2. 1/k+1 : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 18 Jan 2017, 21:10

### 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 k is not 0,1,-1, is 1/k >0? 1. 1/k-1 >0 2. 1/k+1

Author Message
TAGS:

### Hide Tags

Manager
Joined: 21 Dec 2005
Posts: 102
Followers: 1

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

If k is not 0,1,-1, is 1/k >0? 1. 1/k-1 >0 2. 1/k+1 [#permalink]

### Show Tags

09 Apr 2006, 03:30
4
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

59% (01:54) correct 41% (01:11) wrong based on 74 sessions

### HideShow timer Statistics

If k is not 0,1,-1, is 1/k >0?

1. 1/(k-1) >0

2. 1/(k+1) >0

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-k-does-not-equal-0-1-or-1-is-1-k-0-1-1-k-119545.html
[Reveal] Spoiler: OA

Last edited by Bunuel on 08 Aug 2012, 04:03, edited 1 time in total.
Edited the question and added the OA.
SVP
Joined: 24 Sep 2005
Posts: 1890
Followers: 19

Kudos [?]: 292 [0], given: 0

### Show Tags

09 Apr 2006, 04:39
jodeci wrote:
If k is not 0,1,-1, is 1/k >0?

1. 1/k-1 >0

2. 1/k+1 >0

1/ (k-1) > 0 --> k-1> 0 because 1> 0 --> k>1 --> k>0 --> 1/k> 0
-->suff

2/ 1/ ( k+1) > 0 --> k+1> 0 becoz 1> 0 --> k> -1
We don't know if k> 0 ---> impossible to conclude whether 1/k> 0 --> insuff

A it is.
Manager
Joined: 17 Jan 2006
Posts: 92
Followers: 1

Kudos [?]: 17 [0], given: 0

### Show Tags

03 Jun 2006, 23:54
if k is not equal to 0,1, or -1 , is k>0?
1. 1/(k-1)>0
2.1/(k+1)>0
Manager
Joined: 09 May 2006
Posts: 99
Location: Bangalore, India
Followers: 2

Kudos [?]: 40 [0], given: 0

Re: GMATPREP : ds k [#permalink]

### Show Tags

04 Jun 2006, 02:12
dinesh8 wrote:
if k is not equal to 0,1, or -1 , is k>0?
1. 1/(k-1)>0
2.1/(k+1)>0

A

statement 2 allows numbers between -1 to 0 aswell
Manager
Joined: 29 Apr 2006
Posts: 85
Followers: 1

Kudos [?]: 29 [0], given: 0

Re: GMATPREP : ds k [#permalink]

### Show Tags

04 Jun 2006, 09:55
shobhitb wrote:
dinesh8 wrote:
if k is not equal to 0,1, or -1 , is k>0?
1. 1/(k-1)>0
2.1/(k+1)>0

A

statement 2 allows numbers between -1 to 0 aswell

Can you please explain how you came to A?
VP
Joined: 29 Dec 2005
Posts: 1348
Followers: 10

Kudos [?]: 60 [0], given: 0

Re: GMATPREP : ds k [#permalink]

### Show Tags

04 Jun 2006, 10:18
dinesh8 wrote:
if k is not equal to 0,1, or -1 , is k>0?
1. 1/(k-1)>0
2.1/(k+1)>0

(i) 1/(k-1)>0
it has two inequalities: either 1>k-1 or 1<k-1
if 1>k-1, 2>k>1.
if 1<k-1, 2<k. so k must be >1.

2.1/(k+1)>0
1>(k+1)
0>k.

1<(k+1)
k<0. so not enough.........

A.
SVP
Joined: 21 Jul 2006
Posts: 1538
Followers: 10

Kudos [?]: 743 [0], given: 1

DS - positive or negative [#permalink]

### Show Tags

21 Nov 2007, 06:59
If K is not equal to 0, 1, -1, is 1/k >0?

(1) 1/(k-1) >0

(2) 1/(k+1) >0

I chose D, but the OA is A.
In statement 1, the only way it can be positive is to have K greater than or equal to 2, which subsequently 1/k will always be positive.
As for statement 2, the only way it can be positive is also by using a number either greater than or equal to 2 in order to end up with 1/k as positive, yet according to the OA, statement 2 is not suff. can someone explain to me how?
thanks
Manager
Joined: 08 Nov 2007
Posts: 99
Followers: 1

Kudos [?]: 2 [0], given: 0

Re: DS - positive or negative [#permalink]

### Show Tags

21 Nov 2007, 07:03
tarek99 wrote:
If K is not equal to 0, 1, -1, is 1/k >0?

(1) 1/(k-1) >0

(2) 1/(k+1) >0

I chose D, but the OA is A.
In statement 1, the only way it can be positive is to have K greater than or equal to 2, which subsequently 1/k will always be positive.
As for statement 2, the only way it can be positive is also by using a number either greater than or equal to 2 in order to end up with 1/k as positive, yet according to the OA, statement 2 is not suff. can someone explain to me how?
thanks

I got A.

Statement 2 works if say, x = -0.9 as it would read - 1/0.1 >0
However, 1/-0.9 < 0
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 546

Kudos [?]: 3555 [0], given: 360

### Show Tags

21 Nov 2007, 07:18
look at attached drawing.
Attachments

GC55958.gif [ 8.55 KiB | Viewed 2986 times ]

SVP
Joined: 21 Jul 2006
Posts: 1538
Followers: 10

Kudos [?]: 743 [0], given: 1

### Show Tags

21 Nov 2007, 09:49
ok i get it. so you always have to consider the decimals whenever the question doesn't specify that they are integers in the first place.
Intern
Joined: 16 Nov 2007
Posts: 7
Followers: 0

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

denominator gets larger / smaller [#permalink]

### Show Tags

25 Nov 2007, 19:47
if k is not = 0, 1 or -1, is 1/k>0?

1) 1/k-1 >0
2) 1/k+1 >0
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 546

Kudos [?]: 3555 [0], given: 360

### Show Tags

25 Nov 2007, 22:25
does "1/k-1" mean "(1/k)-1" or "1/(k-1)"? Please, write unambiguously
CEO
Joined: 29 Mar 2007
Posts: 2583
Followers: 19

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

Re: denominator gets larger / smaller [#permalink]

### Show Tags

25 Nov 2007, 23:44
jenniferia2002 wrote:
if k is not = 0, 1 or -1, is 1/k>0?

1) 1/k-1 >0
2) 1/k+1 >0

I believe the answer is A.

Im not sure though b/c i dunno if am reading the problem right. agree w/ walker, us paranthesis plz.
SVP
Joined: 05 Jul 2006
Posts: 1743
Followers: 6

Kudos [?]: 316 [0], given: 49

### Show Tags

26 Nov 2007, 00:11
if k is not = 0, 1 or -1, is 1/k>0?

1) 1/k-1 >0
2) 1/k+1 >0

question ask if K is +ve?

from 1

k-1>0 ie> k>1..................suff

from2

k+1>0 ie k>-1 , k is not a must an intiger so it could be = -1/2 or it could be 3 ...insuff

Director
Joined: 03 Sep 2006
Posts: 879
Followers: 6

Kudos [?]: 770 [0], given: 33

### Show Tags

14 Apr 2008, 22:23
If K is not equal to 0,1,-1, is $$1/k > 0$$?

( i ) $$1/(k-1)>0$$

( ii ) $$1/(k+1)>0$$

Last edited by LM on 14 Apr 2008, 23:08, edited 1 time in total.
Senior Manager
Joined: 16 Aug 2004
Posts: 327
Location: India
Followers: 1

Kudos [?]: 47 [0], given: 0

### Show Tags

14 Apr 2008, 22:29
A, as statement b fails when k=-0.5 or any other decimal lower than 1.
Director
Joined: 03 Sep 2006
Posts: 879
Followers: 6

Kudos [?]: 770 [0], given: 33

### Show Tags

14 Apr 2008, 22:50
dushver wrote:
A, as statement b fails when k=-0.5 or any other decimal lower than 1.

Did you plug in the different values of "K" or did you solve the inequality in general? Could you please elaborate on logical approach?
SVP
Joined: 04 May 2006
Posts: 1926
Schools: CBS, Kellogg
Followers: 22

Kudos [?]: 1011 [0], given: 1

### Show Tags

15 Apr 2008, 18:38
LM wrote:
dushver wrote:
A, as statement b fails when k=-0.5 or any other decimal lower than 1.

Did you plug in the different values of "K" or did you solve the inequality in general? Could you please elaborate on logical approach?

LM wrote:
If K is not equal to 0,1,-1, is $$1/k > 0$$?

( i ) $$1/(k-1)>0$$

( ii ) $$1/(k+1)>0$$

A
My reasoning:
the question is similar to k>0?, and keep the condition of k in mind. Go
1, 1/(k-1) >0, again similar to k-1 >0, so k>1, not only satify the conditions but also answer the question. Sufficient
2. again: k+1>0, so k>-1. Stop and think a little. Although combined with the conditions " k is not equal 0, 1, even -1, it still not enought to answer the question. k still can be equal to any fraction running from -1 to 0. Right?
_________________
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 67

Kudos [?]: 734 [0], given: 19

### Show Tags

15 Apr 2008, 20:33
LM wrote:
If K is not equal to 0,1,-1, is $$1/k > 0$$?

( i ) $$1/(k-1)>0$$

( ii ) $$1/(k+1)>0$$

A.

1. k is not -ve. so suff.
2. k could be -ve. nsf
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Manager
Joined: 14 Jun 2009
Posts: 96
Followers: 2

Kudos [?]: 21 [0], given: 9

### Show Tags

11 Aug 2009, 07:07
If k is not equal to 0,1 or -1......Is 1/k >0??

1) 1/(k-1) >0

2) 1/(k+1) >0
k#0,1,-1   [#permalink] 11 Aug 2009, 07:07

Go to page    1   2    Next  [ 33 posts ]

Similar topics Replies Last post
Similar
Topics:
Is k positive? (1) k^5 > 0 (2) -3k < 0 2 14 Jan 2017, 06:44
9 If k does not equal 0, 1 or -1, is 1/k >0 (1) 1/(k-1) > 0 13 24 Aug 2011, 10:24
6 If k is not equal to 0, 1, or -1 is 1/k > 0? 12 10 Aug 2010, 11:05
1 Is K^2 odd? 1) K-1 is divisable by 2 2) The sum of K 5 11 Jun 2010, 03:43
1 If k ≠ 0 , 1 or -1, is 1/k > 0 ? (1) 1 / (k-1) > 0 5 28 Mar 2010, 07:25
Display posts from previous: Sort by