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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

11 Jun 2010, 06:24

11

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

35% (medium)

Question Stats:

68% (01:55) correct
32% (01:05) wrong based on 311 sessions

HideShow timer Statistics

In the xy-plane, line k passes through the point (1, 1) and line m passes through the point (1, -1). Are the lines k and m perpendicular to each other ?

(1) Lines k and m intersect at the point (1, -1) (2) Line k intersects the x-axis at the point (1, 0)

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

11 Jun 2010, 06:33

IMO E.

S1) If line k passes thru (1, 1) and (1, -1) then it is parallel to y axis but we dont know one more different point for line m. Insufficient.

S2) Similar to S1.

S1+S2: Similar to S1, Insufficient.

So, E.
_________________

Want to improve your CR: http://gmatclub.com/forum/cr-methods-an-approach-to-find-the-best-answers-93146.html Tricky Quant problems: http://gmatclub.com/forum/50-tricky-questions-92834.html Important Grammer Fundamentals: http://gmatclub.com/forum/key-fundamentals-of-grammer-our-crucial-learnings-on-sc-93659.html

In the xy-plane ,line k passes through the point (1,1) and line m passes through the point (1,-1).Are the lines k and m perpendicular to each other

(1) Lines k and m intersect at the point (1,-1) (2) Line k intersects the x axis at the point (1,0)

Please help on this DS problem

For one line to be perpendicular to another, their slopes must be negative reciprocals of each other (if slope of one line is \(m\) than the slope of the line perpendicular to this line is \(-\frac{1}{m}\)). In other words, the two lines are perpendicular if and only the product of their slopes is \(-1\).

So basically the question is can we somehow calculate the slopes of these lines.

From stem we have one point for each line.

(1) gives us the second point of line \(k\), hence we can get the slope of this line, but we still know only one point of line \(m\). Not sufficient.

(2) again gives the second point of line \(k\), hence we can get the slope of this line, but we still know only one point of line \(m\). Not sufficient.

(1)+(2) we can derive the slope of line \(k\) but for line \(m\) we still have only one point, hence we can not calculate its slope. Not sufficient.

Answer: E.

For more on this issue please check Coordinate Geometry chapter of Math Book (link in my signature).

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

22 Aug 2010, 17:48

Hey everyone,

Thanks to everyone that responded to my previous round of posts, it was extremely helpful! I have some more questions that I need help with. Here it goes:

In the xy-plane, line k passes through the point (1,1) and line m passes through the point (1,-1). Are lines ka nd m perpendicular to each other?

(1) Lines k and m intersect at the point (1, -1) (2) Line k intersects the x-axis at the point (1,0)

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

22 Aug 2010, 17:53

1. k goes through 1,1 and 1,-1, m can be anyslope. not suff 2. k intersects xaxis at 1,0 <- this probably can be seen from (1) itself. no info about m. not suff 1+2 -> m can be anything. can't say, E
_________________

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

22 Aug 2010, 18:54

uzzy12 wrote:

Thanks for the post but I'm still not grasping the concept. When two lines intersect, doesn't that mean that they are perpendicular to each other?

Yes, when two lines intersect, their angle may or may not be 90 degree. Also we need to find the slope of the two lines (m1 and m2) and for the two lines to be perpendicular, m1 * m2 should be equal to -1.

Since the slope could not be uniquely identified, we cannot conclude that they are perpendicular.
_________________

Support GMAT Club by putting a GMAT Club badge on your blog

I did not understand why you said you can find out only line K slope from statement 1 - why not m

sorry but not able to follow please help

Even when considering the statements together we still know only one point of line m: (1, -1). We cannot get the slope based on just one point of a line.

In the xy-plane, line passes through the point (1,1) and line m passes through the point (1,-1). Are lines k and m perpendicular?

1) Lines k and m intersect at the point (1,-1) 2) Line k intersects the x-axis at the point (1,0)

Merging similar topics.

Val1986 wrote:

Could you tell me how to determine whether the lines are perpendicular just in general??

For one line to be perpendicular to another, their slopes must be negative reciprocals of each other (if slope of one line is \(m\) than the slope of the line perpendicular to this line is \(-\frac{1}{m}\)). In other words, the two lines are perpendicular if and only the product of their slopes is \(-1\).

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

08 May 2015, 07:09

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

In the XY-plane, line K passes through the point (1, 1) and line M passes through point (1, -1). Are lines K and m perpendicular to each other? (1) Lines K and m intersect at the point (1, -1) (2) Line K intersect the x-axis at the point (1, 0)

Re: In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

03 Jun 2016, 23:13

Mahesh91 wrote:

In the XY-plane, line K passes through the point (1, 1) and line M passes through point (1, -1). Are lines K and m perpendicular to each other? (1) Lines K and m intersect at the point (1, -1) (2) Line K intersect the x-axis at the point (1, 0)

In the xy-plane, line k passes through the point (1, 1) and line m [#permalink]

Show Tags

14 Jul 2016, 22:12

gautamsubrahmanyam wrote:

In the xy-plane, line k passes through the point (1, 1) and line m passes through the point (1, -1). Are the lines k and m perpendicular to each other ? (1) Lines k and m intersect at the point (1, -1) (2) Line k intersects the x-axis at the point (1, 0)

Two lines are parallel only if their slopes are inverse reciprocal of each other. (1) Lines k and m intersect at the point (1, -1) Using the (x,y) pair of (1,-1) and other (x,y) pair of (1,1) of line k from the question stem we can see that the slope is undefined. Slope of K = \(\frac{1-(-1)}{1-1} = \frac{-2}{0} ==> undefined\) Meaning Line K is parallel to Y axis and pass through the x axis at x=1, y=0 INSUFFICIENT we have no info about the slope of line K

(2) Line k intersects the x-axis at the point (1, 0) We already know from statement 1 that k passes from x=1. INSUFFICIENT

Merging both statement WE NEED SLOPE OF LINE M But there are only one (x,y) pair given for line M and thus we cannot calculate the slope. and thus cannot compare it with slope of line k Merging also doesn't gives any new information Hence insufficient

ANSWER IS E
_________________

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.

gmatclubot

In the xy-plane, line k passes through the point (1, 1) and line m
[#permalink]
14 Jul 2016, 22:12

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Since my last post, I’ve got the interview decisions for the other two business schools I applied to: Denied by Wharton and Invited to Interview with Stanford. It all...