m03 #15 : GMAT Club Tests

m03 #15

Oldest

Best Reply

Author

Message

Intern

Joined: 09 Jun 2010

Posts: 24

Followers: 0

Kudos [?]: 5 [0], given: 6

m03 #15 [#permalink]

13 Jul 2011, 09:36

00:00

Question Stats:

0% (00:00) correct

0% (00:00) wrong

based on 0 sessions

If two lines have slopes m and n , respectively, are they perpendicular?

1) m*n = -1
2) m=-n

Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
EACH statement ALONE is sufficient
Statements (1) and (2) TOGETHER are NOT sufficient

The explanation says: "Statement (2) by itself is insufficient. We only know that the lines have reciprocal slopes. For example line 10x and -10x , are mirror reflections of each other on the x axis, but not perpendicular."

However since we know they aren't reciprocals we know they aren't perpendicular, thus it is sufficient!

Senior Manager

Joined: 24 Mar 2011

Posts: 479

Location: Texas

Followers: 4

Kudos [?]: 33 [0], given: 20

Re: m03 #15 [#permalink]

13 Jul 2011, 10:02

yes but remember that in data sufficiency both the statements has to give the same answer.

this is yes/no question.
so for each statement to be sufficient both the statements has to be either yes or no.

statement 1 is saying 'yes'. so its sufficient.

statement 1 is saying 'no' so not sufficient.

Answer A.

Intern

Joined: 09 Jun 2010

Posts: 24

Followers: 0

Kudos [?]: 5 [0], given: 6

Re: m03 #15 [#permalink]

13 Jul 2011, 10:04

Wow - Really? I have never heard of this? Where can I read more about it?

Senior Manager

Joined: 24 Mar 2011

Posts: 479

Location: Texas

Followers: 4

Kudos [?]: 33 [0], given: 20

Re: m03 #15 [#permalink]

13 Jul 2011, 10:18

DYNAMITE wrote:

Wow - Really? I have never heard of this? Where can I read more about it?

i think this is very first thing we are suppose to know as part of data sufficient questions. Check in Manhattan Math books, they have this clearly stated.

even otherwise, in DS, ex - if one of the choice says answer is 2/3 for a variable, for other choice to be sufficient answer has to be 2/3 & NOT anything else.

Intern

Joined: 22 Jul 2011

Posts: 1

Followers: 0

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

Re: m03 #15 [#permalink]

23 Jul 2011, 23:40

the statement 2 is not sufficient since, if :

case 1 : if m = 1 , n= -1, which is also -1/m . This satisfies the property for perpendicular lines.

case 2 : if m = 4 , n= -4, which is not -1/m . This does not satisfy the property for perpendicular lines.

Hence , statement 2 does not give us sufficient information.

Re: m03 #15 [#permalink] 23 Jul 2011, 23:40

		Similar topics	Author	Replies	Last post
Similar Topics:	1	m03 - #7	Liquid	13	28 Feb 2008, 22:12
	2	M03 #19	jjhko	19	15 Sep 2008, 12:36
	17	M03 #01	dczuchta	41	19 Sep 2008, 17:06
	1	M03 #15	Hussain15	4	09 Jul 2010, 03:37
	1	m03 #15	vaivish1723	20	31 Jul 2009, 01:21

m03 #15

Moderator: Bunuel

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

m03 #15

m03 #15

Main navigation

GMAT Resources

Partners

MBA Resources