Max@Math Revolution wrote:In the x-y plane there is a line K, (x/a)+(y/b)=1. What is the x-intercept of line K?
1) a = 2b
2) a = 6
Target question: What is the x-intercept of line K?
This is a great candidate for rephrasing the target question.
Aside: We have a video with tips on rephrasing the target question: https://www.gmatprepnow.com/module/gmat- ... cy?id=1100
Given: the equation of line K is (x/a) + (y/b) = 1.
NOTE: The x-intercept is the x-coordinate of the point where the line intersects the x-axis
IMPORTANT: At this intersection point, the y-coordinate = 0
So, let's plug y = 0 into the equation of line K
We get: (x/a) + (0/b) = 1
Simplify: (x/a) = 1
This means that x = a
In other words, the x-intercept of like K is
a
So, we need only find the value of a to answer the target question.
Let's REPHRASE the target question as.....
REPHRASED target question: What is the value of a?
Statement 1: a = 2b
This is not enough info to answer the
REPHRASED target question. There are several values of a and b that satisfy statement 1. Here are two:
Case a: a = 4 and b = 2, in which case
a = 4
Case b: a = 6 and b = 3, in which case
a = 6
Since we cannot answer the
REPHRASED target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: a = 6
PERFECT!!
This allows us to answer the
REPHRASED target question with certainty. So statement 2 is SUFFICIENT
Answer =
B
ASIDE: For more info on finding x and y intercepts, watch this video:
https://www.gmatprepnow.com/module/gmat ... /video/996
Cheers,
Brent
