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

27 Jan 2010, 10:48

00:00

A

B

C

D

E

Difficulty:

45% (medium)

Question Stats:

66% (01:54) correct
34% (00:58) wrong based on 34 sessions

HideShow timer Statistics

Please, explain...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

27 Jan 2010, 15:03

imagine line K extending from (1,1) intersecting the x axis at 1 ,and reachig point (1,-1) and quadrant IV. now line M meets k at (1 , -1) but we dont know to which direction its sloping , could be horizontal at y = -1 or it could be -vely sloped . That doesnt tell us whether the 2 lines are perpindiclar

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

Show Tags

27 Jan 2010, 17:50

To determine if the lines are perpendicular we need to know the slopes of the two lines. Two points are given for line k but only one point is given for line l so it is impossible to find the slope of line l. The two points help us find rise/run which is the slope.

The lines would be perpendicular if the slops of the two lines are negative reciprocals of each other.

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

Show Tags

27 Jan 2010, 21:06

mirzohidjon wrote:

Please, explain...

I'll tell you what your mistake was.

You calculated line K's slope as -infinity and for line m, though it's the same point, you might not have recognized it in your hurry and solved for slope consider the same point as twice, giving you a +infinity as slope. So obviously, they seem perpendicular but actually, product of slopes of perpendicular intersecting lines is supposed to be -1, and we are not sure if product of two infinities is 1.
_________________

There’s something in Pacific North West that you cannot find anywhere else. The atmosphere and scenic nature are next to none, with mountains on one side and ocean on...

This month I got selected by Stanford GSB to be included in “Best & Brightest, Class of 2017” by Poets & Quants. Besides feeling honored for being part of...

Joe Navarro is an ex FBI agent who was a founding member of the FBI’s Behavioural Analysis Program. He was a body language expert who he used his ability to successfully...