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:

Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the y-intercept of the line (the value of \(y\) for \(x=0\)); \(x\) is the independent variable of the function \(y\).

The question is \(b=?\)

(1) The slope of line l is 3 times its y-intercept --> \(m=3b\). Not sufficient to calculate \(b\).

(2) The x-intercept of line l is -1/3 --> x-intercept is the value of \(x\) for \(y=0\) --> \(0=-\frac{1}{3}m+b\) --> \(m=3b\). Same info as above. Not sufficient.

(1)+(2) Nothing new. Not sufficient.

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

Re: What is the y-intercept of the line [#permalink]

Show Tags

18 Sep 2010, 15:26

2

This post received KUDOS

To find: y-intercept of the line. When the line intercepts the y axis, x=0. Hence the original equation y=mx+c becomes y=c. Question asks for the value of c. Statement 1: Slope of the line is 3 times the y intercept. Hence m = 3c. Insufficient.

Statement 2: The x intercept is -1/3. x intercept means y is zero. Hence the original line equation becomes 0=m(-1/3) +c

m = 3c. Same as the first equation. Insufficient.

Combining both yields nothing. Hence the answer is E.
_________________

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

Both equations unsolvable. insuff. E
_________________

I am the master of my fate. I am the captain of my soul. Please consider giving +1 Kudos if deserved!

DS - If negative answer only, still sufficient. No need to find exact solution. PS - Always look at the answers first CR - Read the question stem first, hunt for conclusion SC - Meaning first, Grammar second RC - Mentally connect paragraphs as you proceed. Short = 2min, Long = 3-4 min

I approached this problem as: y = mx + c.....equation of line... (1)

to find C

1) m = 3c.... (2)

substitute (2) in (1)

y = 3cx + c y = c(3x +1)...... (3)

2) X intercept = -1/3

2 implies the line passes through (-1/3,0) doesnt give enough info for M

Combined substitute point (-1/3,0) in (3)

0 = c(3 * -1/3 +1) 0 = c (-1+1 ) c = 0 ?

what did i do wrong ?

From 0=c(-1+1) --> 0=c*0, which holds true for ANY value of c not only for c=0. Also, notice that if c=0, then m=0, thus our line is y=0 which contradicts the statements.

Re: In the xy-plane, what is the y-intercept of line l? [#permalink]

Show Tags

30 Sep 2013, 12:35

testprep2010 wrote:

In the xy-plane, what is the y-intercept of line l?

(1) The slope of line l is 3 times its y-intercept (2) The x-intercept of line l is -1/3

1. y=mx+c

given >> m=3c

y=3cx+c

when y=0, x=-1/3 .. from point -1/3,0 we can draw 2 lines satisfying the condition given above, one with obtuse angle(-ve y intercept) and other with acute angle(+ve y intercept) .. hence, not sufficient

2. x=-1/3 we can draw infinite lines passing from this point .. very clear ..
_________________

Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the y-intercept of the line (the value of \(y\) for \(x=0\)); \(x\) is the independent variable of the function \(y\).

The question is \(b=?\)

(1) The slope of line l is 3 times its y-intercept --> \(m=3b\). Not sufficient to calculate \(b\).

(2) The x-intercept of line l is -1/3 --> x-intercept is the value of \(x\) for \(y=0\) --> \(0=-\frac{1}{3}m+b\) --> \(m=3b\). Same info as above. Not sufficient.

(1)+(2) Nothing new. Not sufficient.

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

Hope it helps.

Hi Bunuel,

In every DS question, if both statements provide the exact same insufficient information and that information is derived in different ways ( slope in (1) and x-intercept in (2) ) , can we assume that both together are insufficient?

Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the y-intercept of the line (the value of \(y\) for \(x=0\)); \(x\) is the independent variable of the function \(y\).

The question is \(b=?\)

(1) The slope of line l is 3 times its y-intercept --> \(m=3b\). Not sufficient to calculate \(b\).

(2) The x-intercept of line l is -1/3 --> x-intercept is the value of \(x\) for \(y=0\) --> \(0=-\frac{1}{3}m+b\) --> \(m=3b\). Same info as above. Not sufficient.

(1)+(2) Nothing new. Not sufficient.

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

Hope it helps.

Hi Bunuel,

In every DS question, if both statements provide the exact same insufficient information and that information is derived in different ways ( slope in (1) and x-intercept in (2) ) , can we assume that both together are insufficient?

Hi Toolong150,

Do not assume anything on DS question unless and until it is obvious.

To your above question, If you get same insufficient information from both statements then ans is E as is above the case. If you look at the above question,actually both statement tell you the same thing but in st1 it talks about slope and st 2 it talks about x intercept

St 1 y= mx+ c says m =3c now if you find x intercept (y=0) we get 0=3cx+c or x=-1/3

Same as st 2

Hope it helps
_________________

“If you can't fly then run, if you can't run then walk, if you can't walk then crawl, but whatever you do you have to keep moving forward.”

Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the y-intercept of the line (the value of \(y\) for \(x=0\)); \(x\) is the independent variable of the function \(y\).

The question is \(b=?\)

(1) The slope of line l is 3 times its y-intercept --> \(m=3b\). Not sufficient to calculate \(b\).

(2) The x-intercept of line l is -1/3 --> x-intercept is the value of \(x\) for \(y=0\) --> \(0=-\frac{1}{3}m+b\) --> \(m=3b\). Same info as above. Not sufficient.

(1)+(2) Nothing new. Not sufficient.

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

Hope it helps.

Hi Bunuel,

I realize that "b' is the y intercept in the equation y = mx + b.

-That being said, I was a little confused as to whether I should solve for B or solve for Y by equation x to 0. If I did the latter, i would get y = b.

-How do I know I I should plug in values for X and Y or solve for B? This part seems to give me the most trouble.

Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the y-intercept of the line (the value of \(y\) for \(x=0\)); \(x\) is the independent variable of the function \(y\).

The question is \(b=?\)

(1) The slope of line l is 3 times its y-intercept --> \(m=3b\). Not sufficient to calculate \(b\).

(2) The x-intercept of line l is -1/3 --> x-intercept is the value of \(x\) for \(y=0\) --> \(0=-\frac{1}{3}m+b\) --> \(m=3b\). Same info as above. Not sufficient.

(1)+(2) Nothing new. Not sufficient.

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

Hope it helps.

Hi Bunuel,

I realize that "b' is the y intercept in the equation y = mx + b.

-That being said, I was a little confused as to whether I should solve for B or solve for Y by equation x to 0. If I did the latter, i would get y = b.

-How do I know I I should plug in values for X and Y or solve for B? This part seems to give me the most trouble.

Thanks

y = b cannot be sufficient. When a DS question asks about the value of some variable, then the statement(s) is sufficient ONLY if you can get the single numerical value of this variable.

Re: In the xy-plane, what is the y-intercept of line l? [#permalink]

Show Tags

10 Dec 2015, 18:30

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.
_________________

After days of waiting, sharing the tension with other applicants in forums, coming up with different theories about invites patterns, and, overall, refreshing my inbox every five minutes to...

I was totally freaking out. Apparently, most of the HBS invites were already sent and I didn’t get one. However, there are still some to come out on...

There is without a doubt a stereotype for recent MBA grads – folks who are ambitious, smart, hard-working, but oftentimes lack experience or domain knowledge. Looking around and at...