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In the rectangular coordinate system shown does the line k
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23 Jul 2008, 07:43
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In the rectangular coordinate system shown does the line k intersect quadrant II? (1) The slope of k is 1/6 (2) The yintercept of k is 6
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Re: DS line k intersect quadrant II?
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15 Oct 2010, 03:02
gmatcraze wrote: Q. In the rectangular coordinate system shown does the line k intersect quadrant II?
1. The slope of k is 1/6 2. The yintercept of k is 6 1. If the slope of line is negative, line WILL intersect quadrants II and IV. X and Y intersects of the line with negative slope have the same sign. Therefore if X and Y intersects are positives, line intersects the quadrant I too, if negative quadrant III. 2. If the slope of line is positive, line WILL intersect quadrants I and III. Y and X intersects of the line with positive slope have opposite signs. Therefor if X intersect is negative, line intersects the quadrant II too, if positive quadrant IV. 3. Every line (but the one crosses origin or parallel to X or Y axis) crosses three quadrants. Only the line which crosses origin (0,0) OR is parallel of either of axis crosses two quadrants. 4. The line with slope 0 is parallel to Xaxis and crosses quadrant I and II, if the Y intersect is positive OR quadrants III and IV, if the Y intersect is negative. If you draw the couple of lines with different slopes you'll understand this better. BACK TO THE ORIGINAL QUESTION:Statement (1) says that slope is negative (case 1) so the line will intersect the quadrants II and IV (line goes from up to down). Sufficient. Statement (2) provides us with yintercept 6, now if line has positive slope then the line goes from down to up and thus won't intersect quadrant II but if the slope is negative then the line goes from up to down thus it will intersect quadrant II. Two different answers. Not sufficient. Answer: A. For more on this topic check Coordinate Geometry chapter of Math Book (link in my signature). Hope it helps.
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Re: DS line k intersect quadrant II?
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23 Jul 2008, 07:49
gmatcraze wrote: Q. In the rectangular coordinate system shown does the line k intersect quadrant II?
1. The slope of k is 1/6 2. The yintercept of k is 6 Answer is C) For line equation you need to know slope and y or x intercept.



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Re: DS line k intersect quadrant II?
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24 Jul 2008, 06:26
nmohindru wrote: gmatcraze wrote: Q. In the rectangular coordinate system shown does the line k intersect quadrant II?
1. The slope of k is 1/6 2. The yintercept of k is 6 Answer is C) For line equation you need to know slope and y or x intercept. but here we don't need to find the line equation, we only need to determine if the line k intersects quadrant II .... how can we determine that? From (1), we know that the line has a negative slope and therefore intersects either quadrant II or quadrant IV. Hence not SUFF. From (2), we know that the point is (0,6). And this lies in quadrant IV. Hence B. Just wondering if my reasoning is correct?



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Re: DS line k intersect quadrant II?
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24 Jul 2008, 06:43
See what I wrote below. Its bold and in red. gmatcraze wrote: nmohindru wrote: gmatcraze wrote: Q. In the rectangular coordinate system shown does the line k intersect quadrant II?
1. The slope of k is 1/6 2. The yintercept of k is 6 Answer is C) For line equation you need to know slope and y or x intercept. but here we don't need to find the line equation, we only need to determine if the line k intersects quadrant II .... how can we determine that? From (1), we know that the line has a negative slope and therefore intersects either quadrant II or quadrant IV[we don't know this because we don't know the yintersect. It could potentially go through all quandrants, but not at the same time of course. Max 3 quandrants at the same time]. Hence not SUFF. From (2), we know that the point is (0,6). And this lies in quadrant IV [something that is actually on the xaxis or yaxis is not IN any quandrant...it is on the axis. Furthermore, with the yintercept at 6, we still don't know which direction the line goes. We only know where it begins. The line could be a y=6 and the line be parallel to the xaxis, or the line could have slope of 1 and it does go through Quadrant II . Hence B. Just wondering if my reasoning is correct?
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Re: DS line k intersect quadrant II?
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24 Jul 2008, 07:04
nmohindru wrote: gmatcraze wrote: Q. In the rectangular coordinate system shown does the line k intersect quadrant II?
1. The slope of k is 1/6 2. The yintercept of k is 6
Answer is C)
For line equation you need to know slope and y or x intercept.
but here we don't need to find the line equation, we only need to determine if the line k intersects quadrant II .... how can we determine that? From (1), we know that the line has a negative slope and therefore intersects either quadrant II or quadrant IV. Hence not SUFF. A line with negative slope will intersect either quadrant I or III. From (2), we know that the point is (0,6). And this lies in quadrant IV. Hence B.
Just wondering if my reasoning is correct?



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Re: DS line k intersect quadrant II?
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24 Jul 2008, 07:05
Hence, the answer should be D.
Stmt 1 implies that the line will either intersect quadrant I or III. Stmt2 implies that the line will intersect quandrant III.



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Re: DS line k intersect quadrant II?
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02 Dec 2008, 21:52
question : does the line k intersect quadrant II ? answer from gmatcraze : From (1), we know that the line has a negative slope and therefore intersects either quadrant II or quadrant IV. The best answer choice is A ( according to GMAt prep)



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Re: DS line k intersect quadrant II?
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04 Oct 2010, 03:30
citing Bunuel from this website.
SLOPE AND QUADRANTS: 1. If the slope of a line is negative, the line WILL intersect quadrants II and IV. X and Y intersects of the line with negative slope have the same sign. Therefore if X and Y intersects are positive, the line intersects quadrant I; if negative, quadrant III. 2. If the slope of line is positive, line WILL intersect quadrants I and III. Y and X intersects of the line with positive slope have opposite signs. Therefore if X intersect is negative, line intersects the quadrant II too, if positive quadrant IV.
Answer is A



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Re: DS line k intersect quadrant II?
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14 Oct 2010, 19:25
A 1) a line with negative slope will intersect 2 and 4  SUFF 2) given point is (0,6)  the line may be going from 3 to 4 to 1 or 4 to 3 to 2. NOT SUFF
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In the rectangular coordinate system does the line k
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20 Mar 2011, 04:07
In the rectangular coordinate system does the line k intersect quadrant II? 1) slope of line k is 1/6 2) the yintercept of line k is 6 OA is provided. I am not sure how the slope alone can help solve this. Please help solve this.



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Re: rectangular coordinate system
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20 Mar 2011, 04:16
As you know the equation of a line is y=kx+b II quadrant means that for x<0 y>0 (1) says that the line is y=1/6x+b. Whatever b you have (positive or negative), this is some finite number. Taking x as low as you can (going to infinity), you always could get 1/6*x as much positive as you need such that the sum 1/6x+b is positive. In other words, solving 1/6*x+b=0 you get the for any x<6b y is positive, obviously for some negative values of x this will also hold. (2) says that y(0)=6 which means that b=6. Is the slope is positive, then such line will never intersect II quadrant. For example y=6+x will never intersect it. So (1) is sufficient, (2) is not. The answer is (A)
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Re: rectangular coordinate system
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20 Mar 2011, 05:30
The answer is A, I think you can visualize this without any calculation. Also, please check MATH book, and Bunuel's tutorials where it's explained what type of lines with what signs pass from which quadrants.
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Re: rectangular coordinate system
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20 Mar 2011, 07:13
It's A. 1. A line with a negative slope always passes through second and fourth quadrant. Thus sufficient Likewise A line with positive slope always passes through First and Third Quadrant.
2. this is insufficient, If the slope of the line is negative, then the line will touch the second quadrant to the left of the y axis & If the slope of the line is positive, or zero (parallel to the x axis), the the line will never touch the second quad.



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Re: rectangular coordinate system
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20 Mar 2011, 08:49
@subhashghosh pls can u send the link to bunuel's post
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Re: rectangular coordinate system
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20 Mar 2011, 22:34
@gmat1220, here you go : mathcoordinategeometry87652.html
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Re: rectangular coordinate system
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20 Mar 2011, 23:18
@subhashghosh thanks so much!
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Re: In the rectangular coordinate system shown does the line k
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