It is currently 23 Jun 2017, 16:06

### 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

# If mn is different from 0, what is the ratio of m to n^2?

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Manager
Joined: 03 Aug 2005
Posts: 134
If mn is different from 0, what is the ratio of m to n^2? [#permalink]

### Show Tags

03 Nov 2005, 01:50
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If mn is different from 0, what is the ratio of m to n^2?

(1) The ratio of m^2 to 1 is 7/5

(2) The ratio of m^2 to n is 7/5
Manager
Joined: 21 Sep 2005
Posts: 232

### Show Tags

03 Nov 2005, 08:59
Ya...with both, I get m/n2 = + or - root(7/5) so E.
Manager
Joined: 17 Sep 2005
Posts: 72
Location: California

### Show Tags

03 Nov 2005, 11:35
E for me too same reason as mohish.

However, I did not have to use the fact that mn not= 0. Not sure what the trap that is?
Manager
Joined: 03 Aug 2005
Posts: 134

### Show Tags

03 Nov 2005, 13:03
E for me too.

OA is C but I think it is wrong.
SVP
Joined: 28 May 2005
Posts: 1707
Location: Dhaka

### Show Tags

03 Nov 2005, 13:28
I got C.

A.The ratio of m^2 to 1 is 7/5 means m^2 /1 = 7/5 we can't solveve ratio of m to n^2

B. The ratio of m^2 to n is 7/5 means m^2/n =7/5 we can't solveve ratio of m to n^2

But if we combine the 2 equation, we get m^2/n =m^2 /1

Since mn is not equal to zero, we can get n=1

so if n = 1 , we can get the value of m which is equal to sqrt(5/7)

now we can calculte the ration of m to n^2 from here.
_________________

hey ya......

Director
Joined: 24 Oct 2005
Posts: 572
Location: NYC

### Show Tags

03 Nov 2005, 13:53
nakib77 wrote:
I got C.

A.The ratio of m^2 to 1 is 7/5 means m^2 /1 = 7/5 we can't solveve ratio of m to n^2

B. The ratio of m^2 to n is 7/5 means m^2/n =7/5 we can't solveve ratio of m to n^2

But if we combine the 2 equation, we get m^2/n =m^2 /1

Since mn is not equal to zero, we can get n=1

so if n = 1 , we can get the value of m which is equal to sqrt(5/7)

now we can calculte the ration of m to n^2 from here.

but when n=1.. m can be +sqrt(7/5)
or m can be -sqrt(7/5)
??
_________________

Success is my only option, failure is not -- Eminem

Manager
Joined: 11 Jul 2005
Posts: 86
Location: New York

### Show Tags

03 Nov 2005, 14:31
According to a Kaplan Coursebook that I have, Unless the 'square root sign' is explicitly given in the question, both positive and negative roots have to be taken into consideration.

But here I feel the answer is C. you donot have to take the roots. The first statement says m^2/1=7/5 .The second statement says m^2/n=7/5.

From St:1 we get M^2= 7/5. Though it is obvious, I am just explaining. Substitute m^2 in statement 2 ,we get n=1. tThere is no need to find the square root.

So the answer is C.
Manager
Joined: 11 Jul 2005
Posts: 86
Location: New York

### Show Tags

03 Nov 2005, 14:33
According to a Kaplan Coursebook that I have, Unless the 'square root sign' is explicitly given in the question, both positive and negative roots have to be taken into consideration.

But here I feel the answer is C. you donot have to take the roots. The first statement says m^2/1=7/5 .The second statement says m^2/n=7/5.

From St:1 we get M^2= 7/5. Though it is obvious, I am just explaining. Substitute m^2 in statement 2 ,we get n=1. tThere is no need to find the square root.

So the answer is C.
Current Student
Joined: 28 Dec 2004
Posts: 3357
Location: New York City
Schools: Wharton'11 HBS'12

### Show Tags

03 Nov 2005, 15:58
this is E...

m^2 can be +-m...so we dont know...m/n

while we agree that n^2 is always positive...that cannot be said about m..
Manager
Joined: 11 Jul 2005
Posts: 86
Location: New York

### Show Tags

03 Nov 2005, 16:09
fresinha12 wrote:
this is E...

m^2 can be +-m...so we dont know...m/n

while we agree that n^2 is always positive...that cannot be said about m..

Am I missing something here? how can m^2 be positive /negative??????I understand m can be +/-

you donot have to find m here. We don't need m/n, we need m^2/n ;Just substitute for m^2 in m^2/n
Director
Joined: 21 Aug 2005
Posts: 789

### Show Tags

03 Nov 2005, 16:16
amy_v wrote:
fresinha12 wrote:
this is E...

m^2 can be +-m...so we dont know...m/n

while we agree that n^2 is always positive...that cannot be said about m..

Am I missing something here? how can m^2 be positive /negative??????I understand m can be +/-

you donot have to find m here. We don't need m/n, we need m^2/n ;Just substitute for m^2 in m^2/n

Question asks for m/n^2
Manager
Joined: 11 Jul 2005
Posts: 86
Location: New York

### Show Tags

03 Nov 2005, 16:19
gsr wrote:
amy_v wrote:
fresinha12 wrote:
this is E...

m^2 can be +-m...so we dont know...m/n

while we agree that n^2 is always positive...that cannot be said about m..

Am I missing something here? how can m^2 be positive /negative??????I understand m can be +/-

you donot have to find m here. We don't need m/n, we need m^2/n ;Just substitute for m^2 in m^2/n

Question asks for m/n^2

you are right!!!!!!!!!!!!!!! silly me!!!!!!!!!!!!!!
SVP
Joined: 24 Sep 2005
Posts: 1885

### Show Tags

03 Nov 2005, 18:19
amy_v wrote:
According to a Kaplan Coursebook that I have, Unless the 'square root sign' is explicitly given in the question, both positive and negative roots have to be taken into consideration.

But here I feel the answer is C. you donot have to take the roots. The first statement says m^2/1=7/5 .The second statement says m^2/n=7/5.

From St:1 we get M^2= 7/5. Though it is obvious, I am just explaining. Substitute m^2 in statement 2 ,we get n=1. tThere is no need to find the square root. So the answer is C.

yeah, but the question asks you to find m/n^2 ...finally, you still have to calculate sqrt(m^2)!
Senior Manager
Joined: 07 Jul 2005
Posts: 402

### Show Tags

03 Nov 2005, 23:52
(1) Insufficient

(2) Insufficietn

(1/2) Sufficient. Combine (1) and (2) and first solve for n. Then solve for m^2. Finally divide n with m^2.
Manager
Joined: 03 Aug 2005
Posts: 134

### Show Tags

04 Nov 2005, 00:24
Question says m/n^2 and m can be +/- sqrt(7/5)
Senior Manager
Joined: 15 Apr 2005
Posts: 415
Location: India, Chennai
Re: DS number properties [#permalink]

### Show Tags

04 Nov 2005, 02:14
jdtomatito wrote:
If mn is different from 0, what is the ratio of m to n^2?

(1) The ratio of m^2 to 1 is 7/5

(2) The ratio of m^2 to n is 7/5

From 1 we get m^2 = 7/5 or m = sqrt(7/5)

From 2 we get m^2/n = 7/5

Combining both we get m^2 = 7/5 and n = 1
=> m = sqrt(7/5) and n^2 = 1
m:n^2 = sqrt(7/5)
Hence C
Manager
Joined: 03 Aug 2005
Posts: 134

### Show Tags

04 Nov 2005, 05:16
Why do not you consider m= - sqrt(7/5)?

If m^2 = 7/5, m = sqrt(7/5) or m = -sqrt (7/5).
04 Nov 2005, 05:16
Display posts from previous: Sort by

# If mn is different from 0, what is the ratio of m to n^2?

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO 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®.