GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Oct 2018, 01:11

### 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

# In the xy – plane, what is the slope of line perpendicular

Author Message
TAGS:

### Hide Tags

Intern
Joined: 27 Sep 2010
Posts: 24
In the xy – plane, what is the slope of line perpendicular  [#permalink]

### Show Tags

23 Jan 2011, 11:38
1
4
00:00

Difficulty:

55% (hard)

Question Stats:

60% (01:25) correct 40% (01:47) wrong based on 174 sessions

### HideShow timer Statistics

In the xy – plane, what is the slope of line perpendicular to line K?

(1) line K intersects line with equation 2x + 3y = 4 at point Q (2,0)
(2) Line K does not intersect line with equation y = 2x-5
Math Expert
Joined: 02 Sep 2009
Posts: 49970
Re: what is the slope of line perpendicular to line K?  [#permalink]

### Show Tags

23 Jan 2011, 12:04
3
MichelleSavina wrote:
Q) In the xy – plane, what is the slope of line perpendicular to line K?
(1) line K intersects line with equation 2x + 3y = 4 at point Q (2,0)
(2) Line K does not intersect line with equation y = 2x-5

In the xy – plane, what is the slope of line perpendicular to line K?

You should know 2 important things:

1. For one line to be perpendicular to another, the relationship between their slopes has to be negative reciprocal, so if the slope of one line is $$m$$ then the line prependicular to it will have the slope $$-\frac{1}{m}$$. In other words, the two lines are perpendicular if and only the product of their slopes is -1.

2. Parallel lines have the same slope.

(1) line K intersects line with equation 2x + 3y = 4 at point Q (2,0) --> clearly insufficient, as we don't know the angle at which the line K intersects this line (we just have some line and know that K intersect it at some point). Not sufficient.

(2) Line K does not intersect line with equation y = 2x-5 --> K is parallel to this line so has the same slope --> slope of K=2 --> the line perpendicular to line K will have the slope -1/2. Sufficient.

For more on these issues check Coordinate Geometry chapter of Math Book: math-coordinate-geometry-87652.html

Hope it helps.
_________________
Manager
Joined: 16 Feb 2012
Posts: 179
Concentration: Finance, Economics
Re: In the xy – plane, what is the slope of line perpendicular  [#permalink]

### Show Tags

02 May 2012, 00:52
If the statement says that ==> Line K does not intersect line with equation y = 2x-5--> K is parallel to this line so has the same slope. How do I know that these two lines are parallel?
_________________

Kudos if you like the post!

Failing to plan is planning to fail.

Math Expert
Joined: 02 Sep 2009
Posts: 49970
Re: In the xy – plane, what is the slope of line perpendicular  [#permalink]

### Show Tags

02 May 2012, 01:02
Stiv wrote:
If the statement says that ==> Line K does not intersect line with equation y = 2x-5--> K is parallel to this line so has the same slope. How do I know that these two lines are parallel?

From definition: two lines in a plane that do not intersect are called parallel lines.

So, K does not intersect line with equation y = 2x-5 means that these lines are parallel.
_________________
Manager
Joined: 16 Feb 2012
Posts: 179
Concentration: Finance, Economics
Re: In the xy – plane, what is the slope of line perpendicular  [#permalink]

### Show Tags

03 May 2012, 05:41
_________________

Kudos if you like the post!

Failing to plan is planning to fail.

Manager
Joined: 07 Jun 2017
Posts: 174
Location: India
Concentration: Technology, General Management
GMAT 1: 660 Q46 V38
GPA: 3.6
WE: Information Technology (Computer Software)
Re: In the xy – plane, what is the slope of line perpendicular  [#permalink]

### Show Tags

22 Oct 2017, 22:14

A. line K intersects line with equation 2x + 3y = 4 at point Q (2,0) - Dont know how much angle it is crating- Not sufficient.
B. Line K does not intersect line with equation y = 2x-5, means parallel lines - Sufficient
_________________

Regards,
Naveen
email: nkmungila@gmail.com
Please press kudos if you like this post

Re: In the xy – plane, what is the slope of line perpendicular &nbs [#permalink] 22 Oct 2017, 22:14
Display posts from previous: Sort by