It is currently 19 Feb 2018, 21:43

### 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 (m+n)3 an odd number? 1) m and n are integers 2) mn=15

Author Message
Senior SC Moderator
Joined: 14 Nov 2016
Posts: 1276
Location: Malaysia
Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

31 Mar 2017, 06:22
3
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

46% (00:48) correct 54% (00:56) wrong based on 24 sessions

### HideShow timer Statistics

Is $$(m+n)^3$$ an odd number?

1) m and n are integers
2) mn=15
[Reveal] Spoiler: OA

_________________

"Be challenged at EVERY MOMENT."

“Strength doesn’t come from what you can do. It comes from overcoming the things you once thought you couldn’t.”

"Each stage of the journey is crucial to attaining new heights of knowledge."

Intern
Joined: 25 Mar 2017
Posts: 10
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

31 Mar 2017, 06:46
For statement 1 if m & n are both odd intergers then (m+n)3 will be even , but if m and n are one even other odd then (m+n)3 will odd so not sufficient

Statement 2 is insufficient as we don't know whether the numbers are integer or not and there can be many possibilities

On combining both statements
MN=15 so the factors will be 5×3
Or 15×1
In both cases we get (m+n)3 to be even hence combining they are sufficient

Sent from my ONEPLUS A3003 using GMAT Club Forum mobile app
Intern
Joined: 15 Mar 2017
Posts: 3
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

31 Mar 2017, 06:56
B. a luck cuz I skipped the last deduction
st. 1 clearly insufficient
st. 2: nm = 15, if n,m = integer - (1;15), (3,5) and so on, => (n+m) even -> answered
if n, m not integer, let say 15/2 and 2 -> far from natural number to be odd (I tried to come up with a formula, but 've failed.)
anyone?
Intern
Joined: 01 Mar 2017
Posts: 3
Location: United States
GPA: 4
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

04 Apr 2017, 15:14
Come on, B is wrong.

Try this:
1) m = 1, n = 15: (m+n) - even, and $$(m+n)^3$$ is also even;
2) m = 9/2+$$\sqrt{21}$$/2, n = 9/2-$$\sqrt{21}$$/2: (m+n) - odd, and $$(m+n)^3$$ is odd

C is the correct answer as both integer decompositions of 15 (3, 5 and 1, 15) give the even (m+n).
Director
Joined: 14 Nov 2014
Posts: 646
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

04 Apr 2017, 22:21
wihi wrote:
Come on, B is wrong.

Try this:
1) m = 1, n = 15: (m+n) - even, and $$(m+n)^3$$ is also even;
2) m = 9/2+$$\sqrt{21}$$/2, n = 9/2-$$\sqrt{21}$$/2: (m+n) - odd, and $$(m+n)^3$$ is odd

C is the correct answer as both integer decompositions of 15 (3, 5 and 1, 15) give the even (m+n).

Selection of numbers in point 2 is awesome ....
The creator of this question missed that complex number selection :p
Senior Manager
Joined: 29 Oct 2016
Posts: 268
Concentration: Finance, Economics
GMAT 1: 620 Q50 V24
GRE 1: 314 Q167 V147
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

08 Apr 2017, 01:34
ziyuen wrote:
Is $$(m+n)^3$$ an odd number?

1) m and n are integers
2) mn=15

Hi Bunuel,
I don't understand why (2) is SUFFICIENT.
if m = 15/4 n = 4,m+n is not integer.Hence,$$(m+n)^{3}$$ can't be considered odd number.
if m = 3 n = 5,$$(m+n)^{3}$$ is even.

Thanks
Math Expert
Joined: 02 Sep 2009
Posts: 43806
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15 [#permalink]

### Show Tags

08 Apr 2017, 03:01
sleepynut wrote:
ziyuen wrote:
Is $$(m+n)^3$$ an odd number?

1) m and n are integers
2) mn=15

Hi Bunuel,
I don't understand why (2) is SUFFICIENT.
if m = 15/4 n = 4,m+n is not integer.Hence,$$(m+n)^{3}$$ can't be considered odd number.
if m = 3 n = 5,$$(m+n)^{3}$$ is even.

Thanks

(2) is not sufficient. It's a poor quality question.

Topic is locked.
_________________
Re: Is (m+n)3 an odd number? 1) m and n are integers 2) mn=15   [#permalink] 08 Apr 2017, 03:01
Display posts from previous: Sort by