If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 10 Feb 2012

Posts: 73

Location: India

Concentration: Marketing, Strategy

GMAT 1: 640 Q48 V31

GPA: 3.45

WE: Science (Health Care)

Followers: 1

Kudos [?]: 10 [2] , given: 41

If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

04 Mar 2012, 22:11

This post received
KUDOS

00:00

Question Stats:

55% (02:04) correct

44% (01:16) wrong

based on 4 sessions

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

(1) (nk)^z > 0, where z is an integer that is not divisible by two
(2) k < n

[Reveal] Spoiler: OA

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11590

Followers: 1798

Kudos [?]: 9582 [1] , given: 826

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

05 Mar 2012, 00:56

This post received
KUDOS

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

First of all: (-2)*n^5>0 --> reduce by negative -2 and flip the sign: n^5<0 --> n<0;
Next: "is k^{37}<0" basically means whether k<0.

So the question becomes: If n and k are integers and n<0 is k<0?

(1) (nk)^z > 0, where z is an integer that is not divisible by two --> (nk)^{odd} > 0 --> nk> 0 --> n and k have the same sign and since n<0 then k<0. Sufficient.

(2) k < n --> since given that n<0 then k<n<0. Sufficient.

Answer: D.
_________________

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!!

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!

What are GMAT Club Tests?
25 extra-hard Quant Tests

Find out what's new at GMAT Club - latest features and updates

SVP

Joined: 01 Sep 2010

Posts: 1747

Followers: 56

Kudos [?]: 580 [0], given: 467

k^37 < 0 [#permalink]

22 Jun 2012, 14:43

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

1) (nk)z > 0, where z is an integer that is not divisible by two

2) k < n

OA later

_________________

KUDOS is the good manner to help the entire community.

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11590

Followers: 1798

Kudos [?]: 9582 [0], given: 826

Re: k^37 < 0 [#permalink]

22 Jun 2012, 14:48

carcass wrote:

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

1) (nk)z > 0, where z is an integer that is not divisible by two

2) k < n

OA later

Merging similar topics. please refer to the solution above.
_________________

SVP

Joined: 01 Sep 2010

Posts: 1747

Followers: 56

Kudos [?]: 580 [0], given: 467

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

22 Jun 2012, 14:54

Bunuel I find this question on the net.......I would like to know if you think that is a good question and if it is elaborate in a good manner.

It is important to practice.

Thanks
_________________

KUDOS is the good manner to help the entire community.

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11590

Followers: 1798

Kudos [?]: 9582 [1] , given: 826

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

23 Jun 2012, 03:58

This post received
KUDOS

carcass wrote:

Bunuel I find this question on the net.......I would like to know if you think that is a good question and if it is elaborate in a good manner.

It is important to practice.

Thanks

Though the question is testing basic concepts usual for the GMAT, I still wouldn't call that question very elegant.
_________________

Intern

Joined: 21 Feb 2013

Posts: 1

Followers: 0

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

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

11 Mar 2013, 18:37

What about the possibility that Z is equal to 0. In that case 1) would be insufficient.

Senior Manager

Joined: 10 Oct 2012

Posts: 285

Followers: 4

Kudos [?]: 94 [0], given: 20

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

11 Mar 2013, 21:47

thekid1998 wrote:

What about the possibility that Z is equal to 0. In that case 1) would be insufficient.

Z can't be zero as it is mentioned that z is not divisible by 2.

Intern

Status: Currently Preparing the GMAT

Joined: 15 Feb 2013

Posts: 23

Location: United States

Schools: HBS '16, Sloan '16, HEC '16

GMAT 1: 550 Q47 V23

GPA: 3.7

WE: Analyst (Consulting)

Followers: 1

Kudos [?]: 22 [0], given: 11

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink]

12 Mar 2013, 07:26

Another great DS problem that helps pinpoint the need to stay alert at the sign of the base of the exponent and whether the power itself is odd or even.

Let's begin by understanding the problem.

We have -2*(n)^5 > 0. Since the power is odd and the end result is positive despite multiplying the expression n^5 by (-2), then this states that n is negative.
So we want to see whether k^(37)<0, which is translated to : is k negative ? since 37 is an odd number !

Statement 1 : (nk)^z > 0, where z is an integer that is not divisible by two

Since z is odd and the expression is positive, we can assume that the base, nk, is positive. And seeing as n is negative, we can say that k is also negative. And since 37 is an odd power, then k^(37) is negative. So statement 1 is sufficient.

Statement 2 : k < n

Since n is negative, it naturally follows that k is also negative. And since 37 is an odd power, then k^(37) is negative. So statement 2 is sufficient.

The correct answer is, therefore, D !

Hope that helped :-D

Re: If n and k are integers and (-2)n^5 > 0, is k^37 < 0? [#permalink] 12 Mar 2013, 07:26

		Similar topics	Author	Replies	Last post
Similar Topics:		if x <> 2, what is the value of ((x-2)^n)/5 +	christoph	7	17 Feb 2005, 14:37
		What is the value of integer k? 1. k + 3 > 0 2. k^4 <= 0	hbs2012	1	24 Dec 2008, 15:10
		If L <> 0 , is an integer? a. (K^2) / (L^2) is an	msand	2	09 May 2010, 03:28
	1	Is m^n >= 0? 1. m< 0 and n is an integer . 2. n<0	surendar26	1	20 Dec 2010, 10:21
		If t > 0, is k < 8	ritumaheshwari02	3	26 Nov 2012, 00:27

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

If n and k are integers and (-2)n^5 > 0, is k^37 < 0?

Main navigation

GMAT Resources

Partners

MBA Resources