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
*An answer will be posted in 2 days.
In the x-y plane there is a line K, (x/a)+(y/b)=1. What is t
This topic has expert replies
- Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
![Image](https://www.mathrevolution.com/img/common/logo.gif)
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
- Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
We can modify the original condition and the question. When the question asks about the x-intercept, we need to find the value of x when y=0. Then, if we substitute y=0, from x/a=1, we get x=a. Hence, we all need to know the value of a. Since the condition 2) states a=6, the condition is sufficient. Thus, the correct answer is B.
- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
- Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
![Image](https://www.mathrevolution.com/img/common/logo.gif)
Math Revolution
The World's Most "Complete" GMAT Math Course!
Score an excellent Q49-51 just like 70% of our students.
[Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions.
[Course] Starting $79 for on-demand and $60 for tutoring per hour and $390 only for Live Online.
Email to : [email protected]
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Target question: What is the x-intercept of line K?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
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