It is currently 17 Oct 2017, 03:03

### 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=m*n^5, where n is an integer and m=4^n. Is K>0? (1)

Author Message
Current Student
Joined: 11 May 2008
Posts: 555

Kudos [?]: 220 [0], given: 0

If K=m*n^5, where n is an integer and m=4^n. Is K>0? (1) [#permalink]

### Show Tags

31 Jul 2008, 20:35
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

16. If K=m*n^5, where n is an integer and m=4^n. Is K>0?
(1) m>m^2
(2) n is an even number.
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Kudos [?]: 220 [0], given: 0

Director
Joined: 23 Sep 2007
Posts: 782

Kudos [?]: 235 [0], given: 0

### Show Tags

31 Jul 2008, 20:44
A

statement 1: m > m^2, this says that 0 < m < 1
that m=4^n, n must be a negative

neg^5 is a negative, and m is positive, so (+)(-) = (-)
so K is negative
suff

statement 2: n is an even number, n can be -2 or 2 or 0
k can be negative or positive or zero
insuff

Last edited by gmatnub on 31 Jul 2008, 20:50, edited 1 time in total.

Kudos [?]: 235 [0], given: 0

Senior Manager
Joined: 06 Mar 2006
Posts: 490

Kudos [?]: 269 [0], given: 1

### Show Tags

31 Jul 2008, 20:47
arjtryarjtry wrote:
16. If K=m*n^5, where n is an integer and m=4^n. Is K>0?
(1) m>m^2
(2) n is an even number.
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Since m=4^n, m is always going to be greater than 0.
The question asks you is k>0. If you already know m>0, the question is really asking you whether n is positive or negative.
Statement 2, by itself is not sufficient as an even number can be both positive or negative
Statement 1, however is sufficient. If m>m^2 and m=4^n, this tell you that m has to be a fraction, only in a situation of fraction, you will find m>m^2. If m is a faction, which means n has to be a negative number. Thus k will be less than 0.

Kudos [?]: 269 [0], given: 1

SVP
Joined: 28 Dec 2005
Posts: 1546

Kudos [?]: 178 [0], given: 2

### Show Tags

01 Aug 2008, 04:40
i get A

from stat 1, m(1-m)>0, so either m>0 and 1-m>0 or m<0 and 1-m<0. The second condition doesnt work, so we have 0<m<1.

This means that n must be negative, and if n is negative, since is it raised to an odd power (5, in this case), that term will always be negative, thus making the entire expression negative.

from stat 2, we dont know if n is positive or negative; the answers are different in each case. insuff.

Kudos [?]: 178 [0], given: 2

SVP
Joined: 07 Nov 2007
Posts: 1792

Kudos [?]: 1057 [0], given: 5

Location: New York

### Show Tags

01 Aug 2008, 08:06
arjtryarjtry wrote:
16. If K=m*n^5, where n is an integer and m=4^n. Is K>0?
(1) m>m^2
(2) n is an even number.
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

1) m>m^2 --> 0>m>1

m=4^n --> "n" must be negative for integer
So K=m*n^5=4^n * n^5 always <0 (because n^5 -- always negative and m is +)

stat 1 is sufficient

2)

K =4^n * n^5 ( assume n=2)
K >0
assume N=-2
K<0

state 2 is Not sufficient.

_________________

Smiling wins more friends than frowning

Kudos [?]: 1057 [0], given: 5

VP
Joined: 17 Jun 2008
Posts: 1374

Kudos [?]: 406 [0], given: 0

### Show Tags

03 Aug 2008, 00:06
arjtryarjtry wrote:
16. If K=m*n^5, where n is an integer and m=4^n. Is K>0?
(1) m>m^2
(2) n is an even number.
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

(1) is sufficient since sign of K depends on whether n is +ve or -ve since m is always +ve => m> m^2 implie n <0 => K<0 => sufficient
(2) this is insufficient since sign of n is not known

_________________

cheers
Its Now Or Never

Kudos [?]: 406 [0], given: 0

Re: IS k>0?   [#permalink] 03 Aug 2008, 00:06
Display posts from previous: Sort by