It is currently 13 Aug 2020, 18:36
My Tests

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.

In the xy-coordinate system, if (a,b) and (a+3, b+k) are two

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Founder
Founder
User avatar
Joined: 18 Apr 2015
Posts: 12642
Followers: 268

Kudos [?]: 3171 [0], given: 11677

CAT Tests
In the xy-coordinate system, if (a,b) and (a+3, b+k) are two [#permalink] New post 29 Jul 2020, 10:47
Expert's post
00:00

Question Stats:

77% (01:22) correct 22% (01:41) wrong based on 9 sessions
In the xy-coordinate system, if (a,b) and (a+3, b+k) are two points on the line defined by the equation x=3y-7, then k=?

A. 9
B. 3
C. 7/3
D. 1
E. 1/3


Kudos for the right answer and explanation
[Reveal] Spoiler: OA

_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

1 KUDOS received
GRE Instructor
User avatar
Joined: 10 Apr 2015
Posts: 3675
Followers: 142

Kudos [?]: 4246 [1] , given: 67

CAT Tests
Re: In the xy-coordinate system, if (a,b) and (a+3, b+k) are two [#permalink] New post 29 Jul 2020, 11:07
1
This post received
KUDOS
Expert's post
Carcass wrote:
In the xy-coordinate system, if (a,b) and (a+3, b+k) are two points on the line defined by the equation x=3y-7, then k=?

A. 9
B. 3
C. 7/3
D. 1
E. 1/3


Kudos for the right answer and explanation


Key Concept: If a point lies ON a line, then the coordinates (x and y) of that point must SATISFY the equation of that line.

Given equation: x = 3y - 7
One point ON the line is (a, b)
So, we can write: a = 3b - 7

Another point ON the line is (a + 3, b + k)
So, we can write: a + 3 = 3(b + k) - 7
Expand: a + 3 = 3b + 3k - 7
Subtract 3 from both sides to get: a = 3b + 3k - 10

We now two equations:
a = 3b + 3k - 10
a = 3b - 7

Subtract the bottom equation from the top equation to get: 0 = 3k - 3
Add 3 to both sides: 3 = 3k
Solve: k = 1

Answer: D

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com
If you enjoy my solutions, you'll like my GRE prep course.
Image
Sign up for GRE Question of the Day emails

Manager
Manager
User avatar
Joined: 02 May 2020
Posts: 90
Followers: 1

Kudos [?]: 67 [0], given: 14

CAT Tests
Re: In the xy-coordinate system, if (a,b) and (a+3, b+k) are two [#permalink] New post 29 Jul 2020, 11:33
Equation of line is x=3y-7
It can be written as
y = (1/3)*x + (7/3)
=> slope = 1/3

Since, (a,b) and (a+3, b+k) also lie on the line
slope can also be written as
slope = (b+k-b)/(a+3-a)
=> 1/3 = k/3
=> k = 1

So, the answer is D.
Re: In the xy-coordinate system, if (a,b) and (a+3, b+k) are two   [#permalink] 29 Jul 2020, 11:33
Display posts from previous: Sort by

In the xy-coordinate system, if (a,b) and (a+3, b+k) are two

  Question banks Downloads My Bookmarks Reviews Important topics  


GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.