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In the xyplane, what is the yintercept of line l?
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28 Feb 2010, 20:51
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In the xyplane, what is the yintercept of line l? (1) The slope of line l is 3 times its yintercept (2) The xintercept of line l is 1/3 Attachment:
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Re: In the xyplane, what is the yintercept of line l?
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01 Mar 2010, 01:42
testprep2010 wrote: Source: GMATPrep Please solve this question (with explanation): In the xyplane, what is the yintercept of line l? 1. The slope of line l is 3 times its yintercept 2. The xintercept of line l is 1/3 Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the yintercept 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 yintercept > \(m=3b\). Not sufficient to calculate \(b\). (2) The xintercept of line l is 1/3 > xintercept 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.
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Re: In the xyplane, what is the yintercept of line l?
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23 Aug 2010, 19:47
uzzy12 wrote: In the xyplane, what is the yintercept of line l?
(1) The slope of line l is 3 itmes the yintercept (2) The xintercept of line l is 1/3 My attempt: Line equation  y = mx +c We need the value of c which the yintercept of the line. Statement 1: Slope is 3 times the y intercept. Hence dy/ dx = 3c. or m = 3c or c = m/3. Without m we cannot identify the value of c. Insufficient. Statement 2: X intercept of the line is 1/3. X intercept => 0 = m*x+c 0 = m (1/3) + c c = (1/3) * m. Without m, we cannot determine c. Insufficient. Combining both (1) and (2), we know m = 3c and c = (1/3)m and both are the same. No way to identify c. Hence insufficient. Answer E.
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Re: In the xyplane, what is the yintercept of line l?
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18 Sep 2010, 15:26
To find: yintercept 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.
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Re: In the xyplane, what is the yintercept of line l?
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18 Sep 2010, 16:09
\(y=mx+c\) m > Slope c > Yint This may be rewritten as : \(\frac{x}{c/m} + \frac{y}{c} = 1\) We know that in terms of intercept the equation of the line is : \(\frac{x}{XInt} + \frac{y}{YInt} = 1\) So \(XInt = c/m, YInt = c\) (1)m=3c ... Not enough to say what the value of c is (2)c/m = 1/3 .... Hence m=3c. We know this is not sufficient (1)+(2) : Same as (1) or (2) Hence, answer is {e} ...neither statement enough
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Re: In the xyplane, what is the yintercept of line l?
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09 Dec 2012, 18:32
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 ?



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Re: In the xyplane, what is the yintercept of line l?
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10 Dec 2012, 01:41
uroopesh wrote: 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. Hope it's clear.
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Re: In the xyplane, what is the yintercept of line l?
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30 Nov 2014, 15:47
Bunuel wrote: testprep2010 wrote: Source: GMATPrep Please solve this question (with explanation): In the xyplane, what is the yintercept of line l? 1. The slope of line l is 3 times its yintercept 2. The xintercept of line l is 1/3 Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the yintercept 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 yintercept > \(m=3b\). Not sufficient to calculate \(b\). (2) The xintercept of line l is 1/3 > xintercept 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



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Re: In the xyplane, what is the yintercept of line l?
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01 Dec 2014, 05:39
russ9 wrote: Bunuel wrote: testprep2010 wrote: Source: GMATPrep Please solve this question (with explanation): In the xyplane, what is the yintercept of line l? 1. The slope of line l is 3 times its yintercept 2. The xintercept of line l is 1/3 Equation of a line in point intercept form is \(y=mx+b\), where: \(m\) is the slope of the line; \(b\) is the yintercept 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 yintercept > \(m=3b\). Not sufficient to calculate \(b\). (2) The xintercept of line l is 1/3 > xintercept 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. Hope it's clear.
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Re: In the xyplane, what is the yintercept of line l?
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07 Oct 2018, 22:11
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Re: In the xyplane, what is the yintercept of line l?
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16 Jul 2019, 02:20
Hi Bunuel , I stopped solving and answered C because I thought combining 1 and 2 contained 2 unique equations. But further solving shows that they both end in m=3b. My question is, if statement 1 gave m=3b and statement 2 gave a different equation. Can the answer in that case be C since the 2 equations are distinct? Please help... Thanks.




Re: In the xyplane, what is the yintercept of line l?
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16 Jul 2019, 02:20






