Archit3110 wrote:
Bunuel wrote:
In the XY-plane, lines L and K are parallel. If the Y-intercept of line L is −1, what is the Y-intercept of line K?
(1) The X-intercept of line L is −1.
(2) Line K passes through the point (5, 10).
using stmnt 1: we know L and K are parallel so both slopes would be equal
x intercept of line L (-1,0) and y intercept (0,-1)
eqn of line L would be , y=-x-1 slope is -1 since lines are parallel hence m of line K is also -1, sufficient
stmnt 2: we are given details of only one of the k coordinates (5,10) , hence eqn of line cannot be determined as there can be multiple possibilities of line K being ll to line L (0,-1), hence insufficient
IMO A should be correct...
GMATinsight : how is C correct??
Statement 1 gives us X-intercept of line L and it's Y-intercept also is -1 hence we have unique equation of line L which is y = -x-1
but there are infinite many lines that are parallel to line L and line K can be any one of them where each line will have same slope -1 but different X and Y intercepts hence
NOT SUFFICIENT
Statement 2 gives us only one point on line K but the value of slope of line K (which is same as slope of line L) is unknown hence we can't locate it on X-Y plane
Combining the statements gives us exact graph of line L
also, we know slope of line K now should be -1 and should pass through (5,10) hence there is a unuque graoh and equation of line K hence we can calculate the x and y intercepts of line K
SUFFICIENT
Answer: Option C
I hope this helps!!!
Archit3110