BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

How to approach this kind of a question

Expert replies
by [email protected] » Sun Aug 04, 2013 2:17 am
Line q is defined by the equation y = mx + b, where m < 0. Does line q pass through (5,4)?

(1) When it is reflected around the x-axis, line q passes through (3,-4)

(2) When it is reflected around the y-axis, line q passes through (-5,3)
Join the discussion
Source: — Problem Solving |

by nipunranjan » Sun Aug 04, 2013 4:35 am
1. Since the line reflected around the x axis contains point (3,-4), so the actual line should pass through (3,4). [Mirror reflection of the point around X-axis.]
Now, for the line to pass though (5,4), it should have a zero slope since it is already passing through (3,4). But our question states that slope of the line, m <0. So the line obtained from option 1 can't pass through (5,4). This option is sufficient.

2. Since the line reflected around the y axis contains point (-5,3), so the actual line should pass through (5,3). [Mirror reflection of the point around Y-axis.]
Now, for the line to pass though (5,3), it should have an infinite slope since it is already passing through (5,3). But our question states that slope of the line, m <0. So the line obtained from option 1 can't pass through (5,4). This option is sufficient.

Answer= Either of the options is sufficient. Hence D
Join the discussion