Is x^2-y^2>x+y?
1) x<y
2) x+y<0
*Answer will be posted in 2 days.
Is x^2-y^2>x+y?
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
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]
x^2 - y^2 = (x - y)(x + y)Max@Math Revolution wrote:Is x^2-y^2>x+y?
1) x<y
2) x+y<0
So, question is: (x - y)(x + y) > x + y ?
(1) x < y => x - y < 0, no info about x + y. Insufficient
(2) x + y < 0, no info about x - y. Insufficient
(Both) (x - y)(x + y) > 0, x + y < 0 => x^2 - y^2 > x + y. Sufficient
C is the answer.
Last edited by flsh on Thu Jun 16, 2016 7:19 am, edited 1 time in total.
- 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. Then, the question becomes x^2-y^2>x+y? (x-y)(x+y)-(x+y)>0?, (x-y-1)(x+y)>0?. Then, since there are 2 variables, there is high chance that C is the correct answer. Using the condition 1) and the condition 2), the answer is always yes and the conditions are sufficient. Hence, the correct answer is C.
- 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.
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]