Inequalities - GMATPrep
This topic has expert replies
- AleksandrM
- Legendary Member
- Posts: 566
- Joined: Fri Jan 04, 2008 11:01 am
- Location: Philadelphia
- Thanked: 31 times
- GMAT Score:640
-
- Senior | Next Rank: 100 Posts
- Posts: 53
- Joined: Thu May 08, 2008 9:28 am
- Thanked: 1 times
- Followed by:1 members
Answer should be A.
1) 2x-3y=-2= -ve. Since, x^2=+ve => 2x-3y <x^2 Sufficient
2) x>2; y>0 =>2x-3y>4 i.e. 2x-3y = 5,6,7....
Also, x>2 =>x^2>4 i.e. x^2 = 5,6,7....
Now if 2x-3y = 5 and x^2 =6 then Left side < Right side.
If 2x-3y = 6 and x^2 = 5 then LS > RS. Not sufficient.
1) 2x-3y=-2= -ve. Since, x^2=+ve => 2x-3y <x^2 Sufficient
2) x>2; y>0 =>2x-3y>4 i.e. 2x-3y = 5,6,7....
Also, x>2 =>x^2>4 i.e. x^2 = 5,6,7....
Now if 2x-3y = 5 and x^2 =6 then Left side < Right side.
If 2x-3y = 6 and x^2 = 5 then LS > RS. Not sufficient.
-
- Master | Next Rank: 500 Posts
- Posts: 288
- Joined: Thu Jul 31, 2008 10:54 pm
- Location: Bombay, India
-
- Newbie | Next Rank: 10 Posts
- Posts: 4
- Joined: Mon Aug 04, 2008 9:49 am
-
- Master | Next Rank: 500 Posts
- Posts: 288
- Joined: Thu Jul 31, 2008 10:54 pm
- Location: Bombay, India
- AleksandrM
- Legendary Member
- Posts: 566
- Joined: Fri Jan 04, 2008 11:01 am
- Location: Philadelphia
- Thanked: 31 times
- GMAT Score:640
The answer is D. However, I would like to know more than just the correct answer, which I already knew. I want to know WHY the answer is D and HOW you would get there. Thanks.
(1) Sufficient because:
=> x^2 is always +ve.
=> given 2x - 3y = -2, which is -ve.
=> Since a -ve num < +ve num, we can say with certainty that 2x - 3y < x^2.
(2) Sufficient because:
=> Given x > 2, y > 0
=> Note that for all n > 2, 2n < n^2 ( you can plug numbers in)
=> Also given that y > 0, so 2n - 3y further reduces the Left hand side.
Therefore, Ans is D
=> x^2 is always +ve.
=> given 2x - 3y = -2, which is -ve.
=> Since a -ve num < +ve num, we can say with certainty that 2x - 3y < x^2.
(2) Sufficient because:
=> Given x > 2, y > 0
=> Note that for all n > 2, 2n < n^2 ( you can plug numbers in)
=> Also given that y > 0, so 2n - 3y further reduces the Left hand side.
Therefore, Ans is D
AleksandrM wrote:The answer is D. However, I would like to know more than just the correct answer, which I already knew. I want to know WHY the answer is D and HOW you would get there. Thanks.