Refelction

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Refelction

by Deepthi Subbu » Sun Jan 16, 2011 12:55 am
Lines a and b have different y-intercepts. When line a is reflected around the y-axis, is its reflection parallel to line b?

(1) Line a is perpendicular to line b.

(2) The slope of line b > 0
Source: — Data Sufficiency |

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by Anurag@Gurome » Sun Jan 16, 2011 1:16 am
Deepthi Subbu wrote:Lines a and b have different y-intercepts. When line a is reflected around the y-axis, is its reflection parallel to line b?

(1) Line a is perpendicular to line b.
(2) The slope of line b > 0
Sometimes coordinate geometry problems can be easily solved by drawing the figure.

Statement 1: Line a is perpendicular to line b.
This is not enough to conclude whether reflection of line a around the y-axis is parallel to b or not.

Not sufficient

Statement 2: The slope of line b > 0
No information about line a.

Not sufficient

1 & 2 Together: Refer to the figure below

Image

Not sufficient

The correct answer is E.
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by ankur.agrawal » Sun Jan 16, 2011 4:12 am
Anurag@Gurome wrote:
Deepthi Subbu wrote:Lines a and b have different y-intercepts. When line a is reflected around the y-axis, is its reflection parallel to line b?

(1) Line a is perpendicular to line b.
(2) The slope of line b > 0
Sometimes coordinate geometry problems can be easily solved by drawing the figure.

Statement 1: Line a is perpendicular to line b.
This is not enough to conclude whether reflection of line a around the y-axis is parallel to b or not.

Not sufficient

Statement 2: The slope of line b > 0
No information about line a.

Not sufficient

1 & 2 Together: Refer to the figure below

Image

Not sufficient

The correct answer is E.
Brilliant Explanation. Thanx.