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by rohu27 » Wed Feb 16, 2011 8:07 am
In the xy-coordinate system, do any points on line k lie in quadrant III?

(1) Line k has y-intercept 2

(2) Line k has slope 2/3

[spoiler]OA:B
Can someoe please explain how to plot the slope in a graph, and also why cant the line just end in second quadrant, why do we need to consider the extension and then say it would definitely pass through 3rd quadrant.
I think m missing some basic concepts here. Help![/spoiler]
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Source: — Data Sufficiency |

by GMATGuruNY » Wed Feb 16, 2011 8:34 am
rohu27 wrote:In the xy-coordinate system, do any points on line k lie in quadrant III?

(1) Line k has y-intercept 2

(2) Line k has slope 2/3

[spoiler]OA:B
Can someoe please explain how to plot the slope in a graph, and also why cant the line just end in second quadrant, why do we need to consider the extension and then say it would definitely pass through 3rd quadrant.
I think m missing some basic concepts here. Help![/spoiler]
A line, by definition, extends forever in each direction. A line segment has endpoints at each end.

Thus:
If a line has a positive slope and a positive y intercept, it will pass through quadrants I, II, and III:
Image

If a line has a positive slope and passes through the origin, it will pass through quadrants I and III:
Image

If a line has a positive slope and a negative y intercept, it will pass through quadrants I, III, and IV.
Image

Thus, statement 2 is sufficient. As we can see above, a line with a positive slope will always pass through quadrant III.

The correct answer is B.
Last edited by GMATGuruNY on Wed Feb 16, 2011 9:41 am, edited 1 time in total.
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by ankur.agrawal » Wed Feb 16, 2011 9:13 am
Sorry Guru did not get the concept. Can u pls show it on a graph. I am confused.

Thanks in advance.
GMATGuruNY wrote:
rohu27 wrote:In the xy-coordinate system, do any points on line k lie in quadrant III?

(1) Line k has y-intercept 2

(2) Line k has slope 2/3

[spoiler]OA:B
Can someoe please explain how to plot the slope in a graph, and also why cant the line just end in second quadrant, why do we need to consider the extension and then say it would definitely pass through 3rd quadrant.
I think m missing some basic concepts here. Help![/spoiler]
A line, by definition, extends forever in each direction. A line segment has endpoints at each end.

Thus:
If a line has a positive slope and a positive y intercept, it will pass through quadrants 1, 2, and 3.
If a line has a positive slope and passes through the origin, it will pass through quadrants 1 and 3.
If a line has a positive slope and a negative y intercept, it will pass through quadrants 1, 3, and 4.

Thus, statement 2 is sufficient. As we can see above, a line with a positive slope will always pass through quadrant 3.

The correct answer is B.
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by GMATGuruNY » Wed Feb 16, 2011 9:43 am
ankur.agrawal wrote:Sorry Guru did not get the concept. Can u pls show it on a graph. I am confused.

Thanks in advance.
GMATGuruNY wrote:
rohu27 wrote:In the xy-coordinate system, do any points on line k lie in quadrant III?

(1) Line k has y-intercept 2

(2) Line k has slope 2/3

[spoiler]OA:B
Can someoe please explain how to plot the slope in a graph, and also why cant the line just end in second quadrant, why do we need to consider the extension and then say it would definitely pass through 3rd quadrant.
I think m missing some basic concepts here. Help![/spoiler]
A line, by definition, extends forever in each direction. A line segment has endpoints at each end.

Thus:
If a line has a positive slope and a positive y intercept, it will pass through quadrants 1, 2, and 3.
If a line has a positive slope and passes through the origin, it will pass through quadrants 1 and 3.
If a line has a positive slope and a negative y intercept, it will pass through quadrants 1, 3, and 4.

Thus, statement 2 is sufficient. As we can see above, a line with a positive slope will always pass through quadrant 3.

The correct answer is B.
Please revisit my original response, to which graphs have been added.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion