Find all School-related info fast with the new School-Specific MBA Forum

It is currently 17 Sep 2014, 00:02

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If p and q are distinct lines in the xy coordinate system

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 28 Aug 2013
Posts: 1
Followers: 0

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

If p and q are distinct lines in the xy coordinate system [#permalink] New post 28 Aug 2013, 19:36
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

52% (02:03) correct 48% (01:53) wrong based on 29 sessions
If p and q are distinct lines in the xy coordinate system such that the equation for p is y= ax + b and the equation for q is y= cx + d, is ac = a²?

(1) d = b + 2
(2) For each point (x, y) on p, there is a corresponding point (x, y + k) on q for some constant x.

I read this question in Princeton Review. In answer part, they show this:
ac = a² so a = c. But if a = 2 and c = -2, for example? I can't get it.
[Reveal] Spoiler: OA
2 KUDOS received
Manager
Manager
avatar
Joined: 17 Mar 2014
Posts: 51
Followers: 0

Kudos [?]: 18 [2] , given: 30

If p and q are distinct lines in the xy coordinate system [#permalink] New post 22 Aug 2014, 06:08
2
This post received
KUDOS
leekaru14 wrote:
If p and q are distinct lines in the xy coordinate system such that the equation for p is y= ax + b and the equation for q is y= cx + d, is ac = a²?

(1) d = b + 2
(2) For each point (x, y) on p, there is a corresponding point (x, y + k) on q for some constant x.

I read this question in Princeton Review. In answer part, they show this:
ac = a² so a = c. But if a = 2 and c = -2, for example? I can't get it.


I think statement 2 should read " for some constant k"

is ac = a²?
or is ac-a^2= 0 --> a(c-a)= 0 --> either a = 0 or a = c
so we need to know if both the lines have same slope or is the slope of line p = 0

(1) d = b + 2 -> nothing about the slopes , just says line q has y intercept which is 2 greater than the y intercept of p, they could still be parallel and have the same slope or not be parallel and differ in slope.

also line y could have 0 slope or not , Hence insufficient

2) For each point (x, y) on p, there is a corresponding point (x, y + k) on q for some constant k.

let 2 points on P be (2, 3) and (5, 7 ) ( we can take any 2 points )

for each of these 2 points on P there will be 2 points on q such that ( 2, 5) and ( 5, 9 ) here taking k as 2
( x coordinates of points on q remains same as those points in line P and Y co ordinates are increased by a constant k )

now slope is (y2- y1)/ (x2- x1)
if we find the slopes of line P and q taking points according to statement 2 , as shown above then both lines will have same slope
hence a= c , sufficient

( Obviously k can vary , still both the lines will give same slope )
If p and q are distinct lines in the xy coordinate system   [#permalink] 22 Aug 2014, 06:08
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic In the xy-coordinate system, do any points on line k lie in enigma123 7 15 Feb 2012, 16:10
In the xy-coordinate system, what is the slope of the line neelesh 0 04 Apr 2008, 21:12
In the xy-coordinate system, what is the slope of the line iamba 9 01 Jul 2007, 10:33
11 In the xy-coordinate system, what is the slope of the line ArvGMAT 11 16 Jun 2007, 19:01
Q: In a rectangular coordinate system, does the line k Summer3 11 18 Mar 2007, 15:27
Display posts from previous: Sort by

If p and q are distinct lines in the xy coordinate system

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.