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Slope of Line

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Source: — Data Sufficiency |
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Re: Slope of Line

by sudhir3127 » Mon Aug 18, 2008 12:01 pm
Baskaranselva wrote:Can someone let me know, how to resolve this question ?

Thanks in advance.
the very simple logic here is to understand that we know the slope is negative . and for an equation ax + by + c=0 the slope is -a/b

hence it cant be zero and a negative number will make the slope positive..

hence choose a positive value.. which is 6.

hope it helps..
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by parallel_chase » Mon Aug 18, 2008 12:16 pm
I think Sudhir posted the correct solution for the wrong question. The above solution is for the other slope question you posted.

Statement I and II alone are insufficient, because we need both the intercepts to find the slope since no other information is given.

Slope of the line = -a/b

a is the x intercept
b is the y intercept.


slope = -2/3

Hence C is the answer.
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by bha » Mon Aug 18, 2008 12:45 pm
parallel_chase wrote:I think Sudhir posted the correct solution for the wrong question. The above solution is for the other slope question you posted.

Statement I and II alone are insufficient, because we need both the intercepts to find the slope since no other information is given.

Slope of the line = -a/b

a is the x intercept
b is the y intercept.


slope = -2/3

Hence C is the answer.
Shouldn't the slope be -3/2...y-intercept/x-intercept...
slope = (y2-y1)/(x2-x1)= (3-0)/(0-2)= -3/2...
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by California4jx » Mon Aug 18, 2008 12:58 pm
By just knowing an x-intercept - a line could be parallel to y-axis or it can make some slope (in that case you need to know y-intercept) - so I is insufficient

Similarly, just knowing y-intercept could mean a line could be parallel to x-axis or may be making a slop for which you need to know x-intercept
thus, statement II is insuffient

Therefore, by combining statement I and II - you get both x and y intercept to know where the line is heading - and there can find the slope

m = y2 - y1/x2-x1
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@ parallel_chase & bha

by rishi235 » Mon Aug 18, 2008 10:06 pm
Hi...
I also agree with bha...the slope shud b -3/2...

But now that ax+by+c=0,
y = -a/bx - c/b
Comparing with y=mx+c
m=-a/b = -2/3
This is incorrect as here a & b are co-efficients of x & y and in the problem, we r given the x & y intercepts...

So, slope = - (Y int) / (X int)
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