Coordinate geometry

roybudhaditya · Posted: Fri Oct 05, 2007 11:58 am Post subject: Coordinate geometry

Lines n & p lie in the XY plane.Is the slope of line n less that the slope of line p???

A--Line n & p intersect at point (5,1).

B--The Y intercept of line n is greater than the Y intercept of line p.

Anything??????????????

Guest · Posted: Fri Oct 05, 2007 2:31 pm Post subject:

Statement 1) is not sufficient. Knowing only the interception does not tell us anything about the slopes of the two lines.

Statement 2) is not sufficient. Two lines that have the same slope can have different y intercepts.

Statement 1&2 together: From statement 1, we know that the point of intersection is in the first quadrant. There can be 3 different scenarios:

1) where y intercepts of n and p are above the point of intersection- in this case, the slope of both lines will be negative. Statement 2 states that y-intercept of line n is above y-intercept of line p; that means n is steeper than p. Steeper line means bigger slope. But don't forget that we are considering negative slopes in this case, so P>N

2) where y intercept of line n is above the point of intersection and the y intercept of line p is below. In this case, line p will have a positive slope and line n will have a negative slope, so P>N

3) where y intercepts of both lines are below the intersection point. In this case, line p will be steeper than line n, so the slope of line p is higher P>N