It is currently 18 Mar 2018, 06:34

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# In the rectangular coordinate system, line k is defined by the equatio

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 44290
In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

30 Mar 2015, 05:42
2
KUDOS
Expert's post
1
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

65% (00:48) correct 35% (00:36) wrong based on 137 sessions

### HideShow timer Statistics

In the rectangular coordinate system, line k is defined by the equation x - 2y + n = 0. What is the value of n?

(1) The x-intercept of line k is 8.

(2) The y-intercept of line k is -4.

Kudos for a correct solution.
[Reveal] Spoiler: OA

_________________
Intern
Joined: 17 Feb 2015
Posts: 28
GPA: 3
Re: In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

30 Mar 2015, 06:16
Both statements alone are sufficient.

We just need to substitute values of x and y to find out value of n.

X intercept is point of intersection of line with x-axis, so x = 8 and y = 0
Y intercept is point of intersection of line with y-axis, so x = 0 and y = -4
Current Student
Joined: 23 May 2013
Posts: 189
Location: United States
Concentration: Technology, Healthcare
Schools: Stanford '19 (M)
GMAT 1: 760 Q49 V45
GPA: 3.5
In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

30 Mar 2015, 10:43
1
KUDOS
Bunuel wrote:
In the rectangular coordinate system, line k is defined by the equation x - 2y + n = 0. What is the value of n?

(1) The x-intercept of line k is 8.

(2) The y-intercept of line k is -4.

Kudos for a correct solution.

Solving for y, our equation becomes $$y = \frac{x}{2} + \frac{n}{2}$$. We are asked to solve for n. Notice immediately that any two values for x and y would allow us to solve the problem, as then it becomes one equation with one unknown.

1) (8,0) is a point on the line. Sufficient.

2) (0,-4) is a point on the line. Sufficient.

If we wanted to take a further look, we could actually plug in these values and test.

1) 0 = 4 + n/2. n = -8.

2) -4 = n/2. n = -8.

Either option is sufficient. Answer: D
Math Expert
Joined: 02 Sep 2009
Posts: 44290
Re: In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

06 Apr 2015, 05:35
1
KUDOS
Expert's post
Bunuel wrote:
In the rectangular coordinate system, line k is defined by the equation x - 2y + n = 0. What is the value of n?

(1) The x-intercept of line k is 8.

(2) The y-intercept of line k is -4.

Kudos for a correct solution.

MAGOOSH OFFICIAL SOLUTION:
Attachment:

findn_exp.png [ 33.7 KiB | Viewed 1570 times ]

_________________
Board of Directors
Joined: 17 Jul 2014
Posts: 2752
Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30
GPA: 3.92
WE: General Management (Transportation)
Re: In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

12 Nov 2015, 19:06
the equation can be rewritten as:
2y=x+n or y=x/2 + n/2
statement 1 tells us that when y is 0, x is 8. by plugging in the numbers, we can find the value of n - sufficient
statement 2 - it gives directly the value of n/2, thus is sufficient.

D.
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 5034
GMAT 1: 800 Q59 V59
GPA: 3.82
Re: In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

15 Nov 2015, 10:48
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

In the rectangular coordinate system, line k is defined by the equation x - 2y + n = 0. What is the value of n?

(1) The x-intercept of line k is 8.

(2) The y-intercept of line k is -4.

There are 2 variables (m,n) in y=mx+n, but actually, we only need to know n in order to understand the graph, so we only have one variable (n). There are 2 equations given, so there is high chance (D) is our answer.
For condition 1, it passes through (8,0), 8-2*0+n=0, n=-8. This is sufficient.
For condition 2, is passes through (0,-4), and from 0-2(-4)+n=0, n=-8. This is sufficient as well, making the answer (D).

For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$79 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Intern
Joined: 26 Feb 2018
Posts: 25
WE: Sales (Internet and New Media)
Re: In the rectangular coordinate system, line k is defined by the equatio [#permalink]

### Show Tags

06 Mar 2018, 11:50
QA : D for me , rationale :

1. Given : x - 2y + n = 0 , x intercept 8 , we can try (8,0) and plug this into the given equation we get , n= -8 SUFFICIENT
2. y intercept -4 , coordinate ( 0,-4) , if we plug this in the main equation x-2y + n = 0 , We get , 0-2(-4) + n = 0 or n = -8 SUFFICIENT
_________________

" Can't stop learning and failing"

Re: In the rectangular coordinate system, line k is defined by the equatio   [#permalink] 06 Mar 2018, 11:50
Display posts from previous: Sort by