It is currently 24 Nov 2017, 06:21

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the xy-plane, the line k passes through the origin and th

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

3 KUDOS received
Intern
Intern
avatar
Joined: 16 Apr 2010
Posts: 21

Kudos [?]: 99 [3], given: 0

In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 26 Jul 2010, 11:28
3
This post received
KUDOS
7
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

63% (01:10) correct 37% (01:06) wrong based on 299 sessions

HideShow timer Statistics

In the xy-plane, the line k passes through the origin and through the point (a,b), where ab does not equal 0. Is b positive?

(1) The slope of line k is negative

(2) a < b
[Reveal] Spoiler: OA

Kudos [?]: 99 [3], given: 0

Expert Post
4 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42356

Kudos [?]: 133204 [4], given: 12439

In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 26 Jul 2010, 11:32
4
This post received
KUDOS
Expert's post
4
This post was
BOOKMARKED
In the xy-plane, the line k passes through the origin and through the point (a,b), where ab does not equal zero. Is b positive?

(1) The slope of line k is negative. If slope is negative and the line passes through the origin, point (a,b) can be either in the II quadrant or in the IV (a and b have opposite signs). So, b can be positive or negative. Not sufficient.

(2) a < b. Not sufficient by itself.

(1)+(2) a < b and they have opposite signs, means b is positive (point lies in the second quadrant). Sufficient.

Answer: C.

Hope it helps.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 133204 [4], given: 12439

Senior Manager
Senior Manager
User avatar
Status: Time to step up the tempo
Joined: 24 Jun 2010
Posts: 404

Kudos [?]: 259 [0], given: 50

Location: Milky way
Schools: ISB, Tepper - CMU, Chicago Booth, LSB
Re: In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 22 Aug 2010, 19:44
1
This post was
BOOKMARKED
uzzy12 wrote:
In the xy-plane, the line k passes through the origin and through the point (a,b) where ab doesn't equal zero. Is b positive?

(1) The slope of line k is negative
(2) a < b



If the line passes through (0,0) and (a,b), then the equation of the line is

(y-0)/(x-0) = (0-b)/(0-a)

(y/x) = (b/a). Hence y = (b/a)x.

Identified slope is (b/a).

Statement a says that the slope is negative. Thus m = -(b/a). However we cannot deduce whether a is -ve or b is -ve.

Statement 2: Says a<b but does not tell us the sign of a or b.

Combining both statements we know that a is less than b and than slope is negative.

Hence -(b/a) can be possible because of m = (b/(-a)) and that b is positive.

Answer is C. Combining both statements helps us answer the question.
_________________

:good Support GMAT Club by putting a GMAT Club badge on your blog :thanks

Kudos [?]: 259 [0], given: 50

Intern
Intern
avatar
Joined: 07 Nov 2014
Posts: 31

Kudos [?]: 1 [0], given: 26

Re: In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 25 Dec 2014, 12:18
Hi Bunuel,

If the line is passing through the origin, the equation can be either y=x or y=-x. Hence from option B, if a<b, it means that the equation of the line is y=-x and since a<b, a is negative and hence B is positive.

Please let me know the flaw in this thought flow.

Kudos [?]: 1 [0], given: 26

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42356

Kudos [?]: 133204 [0], given: 12439

Re: In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 25 Dec 2014, 12:46
vsaketram wrote:
Hi Bunuel,

If the line is passing through the origin, the equation can be either y=x or y=-x. Hence from option B, if a<b, it means that the equation of the line is y=-x and since a<b, a is negative and hence B is positive.

Please let me know the flaw in this thought flow.


Every line of the form y = mx passes through the origin, not only y = x and y = -x.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 133204 [0], given: 12439

1 KUDOS received
Director
Director
User avatar
Joined: 04 Jun 2016
Posts: 647

Kudos [?]: 379 [1], given: 36

GMAT 1: 750 Q49 V43
In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 14 Jul 2016, 22:56
1
This post received
KUDOS
kilukilam wrote:
In the xy-plane, the line k passes through the origin and through the point (a,b), where ab does not equal 0. Is b positive?

(1) The slope of line k is negative

(2) a < b



Statement 1) The slope of line k is negative
Using this and the stimulus we know that we have a line with negative slope that passes through the origin.
But the point (a,b) can lie either on Q II or on Q IV
In Q II b is positive, But in Q IV b is negative.. so INSUFFICIENT

Statement 2) a<b
Now point a less than point b - Apart from Q IV in which "point a" will always positive and "point" b is always negative, this condition "a<b" can happen in any three of Q I, Q II, Q III
After all all it is saying is magnitude of a is less than magnitude of b .. Possible in Q I, Q II and Q III

Merging the two statements
b has to be greater and line has to pass through Q II or IV, there is only one possible quadrant Q II where a is always -ve b is aways +ve. therefore b>a (always)
This satisfies both ur condition and thus we can say that YES B is positive.
Hence answer is C
_________________

Posting an answer without an explanation is "GOD COMPLEX". The world doesn't need any more gods. Please explain you answers properly.
FINAL GOODBYE :- 17th SEPTEMBER 2016. .. 16 March 2017 - I am back but for all purposes please consider me semi-retired.

Kudos [?]: 379 [1], given: 36

Manager
Manager
User avatar
B
Joined: 03 May 2017
Posts: 107

Kudos [?]: 17 [0], given: 13

Re: In the xy-plane, the line k passes through the origin and th [#permalink]

Show Tags

New post 04 Oct 2017, 23:14
kilukilam wrote:
In the xy-plane, the line k passes through the origin and through the point (a,b), where ab does not equal 0. Is b positive?

(1) The slope of line k is negative

(2) a < b



is b positive?

1. b/a = negative, not sufficient, either b or a could be negative
2. a<b, not sufficient to determine sign of either a or b

Combining 1 and 2 is enough to know b must be positive and a is negative. Hence C

Kudos [?]: 17 [0], given: 13

Re: In the xy-plane, the line k passes through the origin and th   [#permalink] 04 Oct 2017, 23:14
Display posts from previous: Sort by

In the xy-plane, the line k passes through the origin and th

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.