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slope of line

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by pradeepkaushal9518 » Sat May 08, 2010 3:46 am
In the xy-plane, what is the slope of line l?
(1) Line l dose not intersect the line with equation y = 1 - x.
(2) Line l intersects the line with equation y = x - 1.
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Source: — Data Sufficiency |

by iamseer » Sat May 08, 2010 5:05 am
IMO A

From 1:
Line l does intersect a line with slope -1. So line l has to have a slope of -1
Sufficient.

From 2:
Line l intersects a line with slope 1. In that case line l could have any slope other than 1.
Not Sufficient.
"Choose to chance the rapids and dance the tides"
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by gmatmachoman » Sat May 08, 2010 5:16 am
iamseer wrote:IMO A

From 1:
Line l does intersect a line with slope -1. So line l has to have a slope of -1
Sufficient.

From 2:
Line l intersects a line with slope 1. In that case line l could have any slope other than 1.
Not Sufficient.
seer !

how do u say that Line L has to be parallel to that line??? Any lead on that?

I do agree if they are parallel m1 =m2. thats fine. But I am not sure from St1 we get whether they are parallel to each other.

Plz corretc me if i am wrong.
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by iamseer » Sat May 08, 2010 5:23 am
gmatmachoman wrote: seer !

how do u say that Line L has to be parallel to that line??? Any lead on that?

I do agree if they are parallel m1 =m2. thats fine. But I am not sure from St1 we get whether they are parallel to each other.

Plz corretc me if i am wrong.
XY plane extends infinitely. A line extends infinitely in either direction too.

In case of 2 lines, they are either parallel or non-parallel i.e. they intersect each other. This holds true if the lines are in same plane. That is mentioned in the question.


Just for fun and better understanding draw a line on a piece of paper. Now, try drawing another line which does not intersect this line.

HTH!!
"Choose to chance the rapids and dance the tides"
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