GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 27 May 2020, 15:26 ### 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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  # Is m > 0? (1) mn = 15 (2) m + n = 8

Author Message
TAGS:

### Hide Tags

Retired Moderator V
Joined: 27 Oct 2017
Posts: 1787
WE: General Management (Education)
Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

1
1 00:00

Difficulty:   25% (medium)

Question Stats: 83% (01:07) correct 17% (00:40) wrong based on 23 sessions

### HideShow timer Statistics

GMATBusters’ Quant Quiz Question -8

Is m > 0?

(1) mn = 15
(2) m + n = 8

_________________
Retired Moderator V
Joined: 27 Oct 2017
Posts: 1787
WE: General Management (Education)
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

(1) mn= 15 or any positive number
it shows either both m and n are positive or both m and n are negative
NOT Sufficient
(2) m + n= 8 or any positive number
It shows at least one of m and n is positive
NOT Sufficient

Combining Statements 1 & 2, we get both m and n are positive, hence SUFFICIENT

_________________
Intern  B
Joined: 17 Aug 2019
Posts: 21
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

1) If m=-3 and n=-5, then m=-3<0. However, if m=3 and n=5, then m=3>0. Therefore, this statement is clearly insufficient.
2) If m=-4 and n=12, then m=-4<0. However, if m=4 and n=4, then m=4>0. Therefore, this statement is clearly insufficient.
1)+2)
from 2): n=8-m. Plugging this equation into 1)
m(8-m)=15
m^2-8m+15=0
(m-3)(m-5)=0
here m=3 or m=5. In either case m>0. Sufficient.
Senior Manager  P
Joined: 31 May 2017
Posts: 412
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

is m > 0?

(1) mn= 15
(2) m + n= 8

(1) mn = 15

When m=5 , n=3 , then m*n = 15 and m>0
when m=-5, n=-3 , then m*n = 15 and m<0

Option A not sufficient.

(2) m+n = 8
when m=4,n=4 , then m+n = 8 and m >0
when m = -1 , n = 9, then m+n=8 and m<0

Option B is not sufficient

Consider (1) + (2)
m*n = 15 and m+n = 8

Only possible option to satisfy both condition is M=5,N=3 or M=3,N=5 and in both the case m > 0

Ans C
_________________
Intern  B
Joined: 20 Sep 2015
Posts: 27
Location: India
WE: Research (Energy and Utilities)
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

Qs: is m > 0?

(1) mn= 15

no information on sign of m & n, both can be negative or positive.
m=3, n= 5 then mn= 15, so m is positive , hence m>0
if m =-3, n=-5, then mn= 15 but m is negative hence m<0
not sufficient to answer the question.

(2) m + n= 8

this state that at-least one of the variable is positive but which one is not clear. or m can be zero also.
if m = 2, n=6 then m+n= 8 and m is positive
m =-2, n= 10, then m+n= 8 and m is negative. not sufficient to answer the question.

combining, we know from statement -2 that at-least one will be positive and from statement -1, that both should be of same sign. therefore both the variable are positive in sign.

therefore m>0 is possible to determine.

Senior Manager  P
Status: Student
Joined: 14 Jul 2019
Posts: 322
Location: United States
Concentration: Accounting, Finance
GPA: 3.9
WE: Education (Accounting)
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

Is m > 0?

(1) mn= 15
(2) m + n= 8

1) m can be any negative number and in that case if n is also is a negative number, mn can still be equal to an positive number. not sufficient.

2) same as 1, for any negative value of m, n can still cover so that their sum equals to 8. not sufficient.

together, the negative number can be either m or n, which cannot be determined from the information given. not sufficient.

VP  V
Joined: 18 Dec 2017
Posts: 1364
Location: United States (KS)
GMAT 1: 600 Q46 V27 Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

m>0?

Type : Y/N

Statement 1: mn=15
m=3 n=5 gives us Y
m=-3 n=-5 gives us N.

Statement 2: m+n=8
m=3 n=5 gives us Y
m=-5 n=13 gives us N.

Combined:
mn=15
m+n=8 Therefore n=8-m

Substituting n=8-m in mn=15

m(8-m)=15
Gives us a quadratic equation which gives us 2 values of m as 3 and 5. Both are greater than 0.

_________________
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long

Why You Don’t Deserve A 700 On Your GMAT

Learn from the Legend himself: All GMAT Ninja LIVE YouTube videos by topic
You are missing on great learning if you don't know what this is: Project SC Butler
Manager  S
Joined: 05 May 2016
Posts: 142
Location: India
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

Statement 1: mn=15

m=-3, n=-5 or m=3,n=5 so in any of the cases we cannot say for sure if m>0, it could be -1,1 -3,3,-5,5,15,-15.

Not Sufficient.

Statement 2: m+n = 8

Here again, since sum is even, so both m and n are either odd or both are even, so some of the possible combinations could be:

-2+10 = 8,
3+5 = 8
and etc.
So we cannot say for sure, if m > 0. So

Insufficient.

If we combine the 2, we get 2 values of n = 3 and 5, in both cases m will be >0. So,

Intern  B
Joined: 16 Nov 2019
Posts: 8
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

(1) or (2) alone is clearly insufficient.

Both together though are sufficient:
(1) mn=15: m and n must have same sign (positive or negative)
(2) m+n=8: can the sum of two negative (says -3 and -5) be postive?
Nah, therefore m>0 always
GMAT Club Legend  V
Joined: 18 Aug 2017
Posts: 6272
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: Is m > 0? (1) mn = 15 (2) m + n = 8  [#permalink]

### Show Tags

is m > 0?

(1) mn= 15
(2) m + n= 8
#1
mn= ( 3,5) ( -3,-5) ( 15,1) ( 45,1/3) insufficient
#2
m+n = 8
( 8,0) ( 7,1) ( 3,5) .. insufficient
from 1 &2
m,n = 3,5 sufficient
IMO C Re: Is m > 0? (1) mn = 15 (2) m + n = 8   [#permalink] 02 Feb 2020, 01:15

# Is m > 0? (1) mn = 15 (2) m + n = 8  