slope

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slope

by ketkoag » Wed Apr 08, 2009 4:49 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.

My answer is E , but OA: A
I feel my answer to be 99% correct. please explain if i am wrong.
Source: — Data Sufficiency |

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by bluementor » Wed Apr 08, 2009 4:55 am
if 2 lines have the same slope, then they will never intersect. So this means, line l is parallel to y= 1-x. This statement is sufficient on its own.

Choose A.

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by ketkoag » Wed Apr 08, 2009 3:01 pm
oh yes!! i overlooked xy plane..
got it, thanks.....

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Re: slope

by vittalgmat » Wed Apr 08, 2009 3:23 pm
ketkoag wrote: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.

My answer is E , but OA: A
I feel my answer to be 99% correct. please explain if i am wrong.
Indeed the answer should be E.

stmt 1 & 2 dont say anything specific about line L. ie. are they parallel or perpendicular. We cannot determine the slope even by combining 1 and 2.
So E it is.

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by cubicle_bound_misfit » Wed Apr 08, 2009 8:44 pm
This one is a rather sitter.

in x-y plane two lines will never intersect if and only if they are paralle i.e. their slopes are equal.
hence A is sufficient.
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by vittalgmat » Wed Apr 08, 2009 9:46 pm
cubicle_bound_misfit wrote:This one is a rather sitter.

in x-y plane two lines will never intersect if and only if they are paralle i.e. their slopes are equal.
hence A is sufficient.
Super!!! u r right!!!..
missed this.
If two lines are not parallel, they WILL intersect, atleast asymtotically.
But that begs a question.

If the q stem says as above, should I assume that lines are of infinite length??
Only if we assume that, we can conclude that lines are parallel.

Ian/Stuart/Brent/... Pls help.