GMAT Changed on April 16th - Read about the latest changes here

 It is currently 25 May 2018, 04:06

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

D01-15

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 45413

Show Tags

16 Sep 2014, 00:11
1
KUDOS
Expert's post
10
This post was
BOOKMARKED
00:00

Difficulty:

65% (hard)

Question Stats:

59% (01:08) correct 41% (01:10) wrong based on 187 sessions

HideShow timer Statistics

Is $$K$$ a positive number?

(1) $$|K^3| + 1 \gt K$$

(2) $$K + 1 \gt |K^3|$$

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 45413

Show Tags

16 Sep 2014, 00:12
Official Solution:

Statement 1 is insufficient. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO). Both $$K$$ values hold the inequality true.

Statement 2 is insufficient. The logic is the same as in Statement 1. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO).

Combining the two statements doesn't give us new information.

_________________
Intern
Joined: 03 Feb 2015
Posts: 14
GMAT 1: 680 Q47 V36
GMAT 2: 720 Q49 V39

Show Tags

16 Mar 2015, 22:48
hi Bunuel

you wrote-
'Statement 2 is insufficient. The logic is the same as in Statement 2. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO).'

In [highlight]statement 2
if we put value k=0 we will get 1>0. which is true. how is this a No
Math Expert
Joined: 02 Sep 2009
Posts: 45413

Show Tags

17 Mar 2015, 05:33
harDill wrote:
hi Bunuel

you wrote-
'Statement 2 is insufficient. The logic is the same as in Statement 2. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO).'

In [highlight]statement 2
if we put value k=0 we will get 1>0. which is true. how is this a No

The questions asks whether k is a positive number. For (2) if k = 1 (which satisfies second statement) it IS a positive number but if k = 0 (which also satisfies second statement) it is NOT a positive number (0 is not a positive number, it's neither positive nor negative).
_________________
Manager
Joined: 11 Sep 2013
Posts: 149
Concentration: Finance, Finance

Show Tags

17 Mar 2015, 11:54
1
KUDOS
harDill wrote:
hi Bunuel

you wrote-
'Statement 2 is insufficient. The logic is the same as in Statement 2. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO).'

In [highlight]statement 2
if we put value k=0 we will get 1>0. which is true. how is this a No

Your target is to find whether K can be negative or Zero or it is only positive. Remember you have to maintain the condition in statement 2

Now if K is positive, say k=1 statement 2 becomes 1+1> 1 which is true. That means by keeping k positive you can satisfy statement 2

Now if K is negative, say k= -0.5, statement 2 becomes -0.5+1> 0.125 or 0.5> 0.125 which is also true. That means by taking K= negative value you can still satisfy statement 2.

So, K can be positive and negative and zero. Therefore The answer of the question (IS K Positive) can be yes and can be no. Sot sufficient
Intern
Joined: 03 Feb 2015
Posts: 14
GMAT 1: 680 Q47 V36
GMAT 2: 720 Q49 V39

Show Tags

17 Mar 2015, 23:10
Bunuel wrote:
harDill wrote:
hi Bunuel

you wrote-
'Statement 2 is insufficient. The logic is the same as in Statement 2. Consider $$K=1$$ (the answer is YES) and $$K=0$$ (the answer is NO).'

In [highlight]statement 2
if we put value k=0 we will get 1>0. which is true. how is this a No

The questions asks whether k is a positive number. For (2) if k = 1 (which satisfies second statement) it IS a positive number but if k = 0 (which also satisfies second statement) it is NOT a positive number (0 is not a positive number, it's neither positive nor negative).

ok i got it now. i misunderstood the explanation the first time. thanks guys
Intern
Joined: 04 Dec 2015
Posts: 7

Show Tags

20 Feb 2017, 10:47
Hi all,

I successfully demonstrated that both statements taken singularly weren't sufficient to answer, however, I found myself stuck when it came to consider them together.
Being uncertain between C and E I simply guessed C..

..how can you say that the two statements are not providing any new information? They're not an identity nor equivalent, so I spent valuable seconds trying to figure out the possible scenarios when combining them.
Manager
Joined: 14 Jun 2016
Posts: 70
Location: India
GMAT 1: 600 Q49 V21
WE: Engineering (Manufacturing)

Show Tags

22 Aug 2017, 10:44
Is there any alternative way rather than just value plugging ?
_________________

If you appreciate my post then please click +1Kudos

Math Expert
Joined: 02 Sep 2009
Posts: 45413

Show Tags

22 Aug 2017, 10:51
buan15 wrote:
Is there any alternative way rather than just value plugging ?

Check here: https://gmatclub.com/forum/gmat-diagnos ... 79342.html
_________________
Manager
Joined: 11 Jun 2016
Posts: 75
Location: India
GMAT 1: 680 Q49 V35
GMAT 2: 690 Q49 V34
GPA: 3.4

Show Tags

16 Nov 2017, 06:43
Bunuel,

i could see that both the statements individually are insufficient. But i wasn't sure if combing them would make them sufficient .
Intern
Joined: 31 Dec 2017
Posts: 1

Show Tags

17 Jan 2018, 12:34
Hi everyone,

After demonstrating that each statement alone is not sufficient (by plugging in numbers), I proved that E is the correct answer by adding the two inequalities together:

(1) |K^3|+1>K
(2) K+1>|K^3|
Added together: |K^3|+ K+ 2 > |K^3| + K

After substracting (|K^3| + K) from both sides we get: 2 > 0, which is always true; therefore K can be any number, not only a positive one - the statements taken together are still not sufficent
Manager
Joined: 28 Dec 2016
Posts: 88
Location: United States (IL)
Concentration: Marketing, General Management
Schools: Johnson '20 (M)
GMAT 1: 700 Q47 V38

Show Tags

31 Mar 2018, 19:11
1
KUDOS
Bunuel
Excellent question. Not a big deal, but small typo in your explanation:
"Statement 2 is insufficient. The logic is the same as in Statement 2."
"Statement 2 is insufficient. The logic is the same as in Statement 1."
Math Expert
Joined: 02 Sep 2009
Posts: 45413

Show Tags

01 Apr 2018, 02:27
CPGguyMBA2018 wrote:
Bunuel
Excellent question. Not a big deal, but small typo in your explanation:
"Statement 2 is insufficient. The logic is the same as in Statement 2."
"Statement 2 is insufficient. The logic is the same as in Statement 1."

Thank you. Edited.
_________________
Re: D01-15   [#permalink] 01 Apr 2018, 02:27
Display posts from previous: Sort by

D01-15

Moderators: chetan2u, Bunuel

 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®.