Is my approach right? : Quant Question Archive [LOCKED]
Check GMAT Club App Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 10 Dec 2016, 07:01

### 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

# Is my approach right?

Author Message
VP
Joined: 18 May 2008
Posts: 1286
Followers: 15

Kudos [?]: 400 [0], given: 0

### Show Tags

14 Jun 2008, 02:10
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is k^2 + k - 2 > 0

1. k < 1
2. k > -1
In solving above question, i followed the following approach:
k^2 + k - 2=(k-1)(k+2)
In order to above equation to be greater than 0, k should lie between -2 and 1
i.e. -2<k<1. Now
(1) says k<1 but nothing abt -2. SO Insufficient
(2) k>-1 so must be greater than -2 as well but says nothing abt 1. so Insufficient
Combining 1 and 2, we get the answer. So C
Is my approach correct? is there any other way of soving such type of problems?
CEO
Joined: 17 Nov 2007
Posts: 3589
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 531

Kudos [?]: 3457 [0], given: 360

Re: Is my approach right? [#permalink]

### Show Tags

14 Jun 2008, 04:48
ritula wrote:
Is k^2 + k - 2 > 0

1. k < 1
2. k > -1
In solving above question, i followed the following approach:
k^2 + k - 2=(k-1)(k+2)
In order to above equation to be greater than 0, k should lie between -2 and 1
i.e. -2<k<1. Now
(1) says k<1 but nothing abt -2. SO Insufficient
(2) k>-1 so must be greater than -2 as well but says nothing abt 1. so Insufficient
Combining 1 and 2, we get the answer. So C
Is my approach correct? is there any other way of soving such type of problems?

_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Director
Joined: 10 Sep 2007
Posts: 947
Followers: 8

Kudos [?]: 285 [0], given: 0

Re: Is my approach right? [#permalink]

### Show Tags

14 Jun 2008, 04:52
Almost there
For (k-1)(k+2) to be +ve following things should be kept in mind

1) For All +ve K, (k+2) will be always +ve. So for (k-1) to be +ve we can write
k - 1 > 0 => k > 1
1) For All -ve K, (k-1) will be always -ve. So for (k+2) to be -ve we can write
k + 2 < 0 => k < -2
So Range of K = (-Infinity to -2) and (1 to Infinity)

Between -2 < k < 1 will be negative.
But after combining the reasoning given by you still holds.
Director
Joined: 14 Oct 2007
Posts: 758
Location: Oxford
Schools: Oxford'10
Followers: 14

Kudos [?]: 211 [0], given: 8

Re: Is my approach right? [#permalink]

### Show Tags

14 Jun 2008, 12:34
questions such as these, I find that sketching a quick graph after factorization will help you

attached is my sketch and its evident that C is the answer based on the sketch
Attachments

para.jpg [ 3.72 KiB | Viewed 738 times ]

Re: Is my approach right?   [#permalink] 14 Jun 2008, 12:34
Display posts from previous: Sort by