Author 
Message 
TAGS:

Hide Tags

Director
Joined: 07 Jun 2004
Posts: 612
Location: PA

Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
05 Jan 2011, 11:23
2
This post received KUDOS
3
This post was BOOKMARKED
Question Stats:
53% (02:15) correct
47% (01:29) wrong based on 226 sessions
HideShow timer Statistics
Is x between 0 and 1? (1)  x < x^3 (2) x < x^2
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
If the Q jogged your mind do Kudos me : )



Math Expert
Joined: 02 Sep 2009
Posts: 39673

Re: DS Algebra [#permalink]
Show Tags
05 Jan 2011, 11:38
1
This post received KUDOS
Expert's post
1
This post was BOOKMARKED



Director
Joined: 07 Jun 2004
Posts: 612
Location: PA

Re: DS Algebra [#permalink]
Show Tags
05 Jan 2011, 13:48
Bunuel thanks , I had a Q , your approach to these DS algebra has always been using algebra itself to get the answers will this ( should ) work most of the times right ? I prefer your approach as its clear cut rather than plug in values and check more time consuming do share your thoughts on this thanks rxs0005
_________________
If the Q jogged your mind do Kudos me : )



Math Expert
Joined: 02 Sep 2009
Posts: 39673

Re: DS Algebra [#permalink]
Show Tags
05 Jan 2011, 16:28



Manager
Joined: 19 Dec 2010
Posts: 137

Re: DS Algebra [#permalink]
Show Tags
17 Mar 2011, 23:05
pick a positive integer, positive fraction. Negative integer, negative fraction approach to this problem... statement 1 says that x is > 0 (integer or fraction doesn't matter...it satisfies the condition) statement 2 says that x is <0 and >1 hence it never satisfies the original problem. NO is an acceptable answer. Solved. B



SVP
Joined: 16 Nov 2010
Posts: 1663
Location: United States (IN)
Concentration: Strategy, Technology

Re: DS Algebra [#permalink]
Show Tags
18 Mar 2011, 00:32
(1) x < x^3 , this is correct for any +ve fraction, but also for a number > 1, not sufficient. (2) x < x^2 This is correct for any number(ve integer or ve fraction), but also for a number > 1 x< 0 or x > 1, so answer is B
_________________
Formula of Life > Achievement/Potential = k * Happiness (where k is a constant)
GMAT Club Premium Membership  big benefits and savings



Manager
Joined: 16 Feb 2012
Posts: 230
Concentration: Finance, Economics

Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
17 Jul 2012, 13:29
If someone could elaborate the first statement in more detail. From the statement I know that x(x^2 + 1)> 0, so x>0 and x^2 + 1> 1 isn't it? Furthermore, I can conclude that x could be x>0 and x>1, so because I don't know the exact value of x the statement is insufficient. Is that correct?
_________________
Kudos if you like the post!
Failing to plan is planning to fail.



Math Expert
Joined: 02 Sep 2009
Posts: 39673

Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
18 Jul 2012, 02:54
Stiv wrote: If someone could elaborate the first statement in more detail. From the statement I know that x(x^2 + 1)> 0, so x>0 and x^2 + 1> 1 isn't it? Furthermore, I can conclude that x could be x>0 and x>1, so because I don't know the exact value of x the statement is insufficient. Is that correct? Not quite. The question asks: is \(0<x<1\)? The first statement says: \(x(x^2+1)>0\). So, we have that the product of two multiples, \(x\) and \(x^2+1\), is positive. Now, since the second multiple is always positive (\(x^2+1= nonnegative +positive=positive\)), then the first multiple must also be positive in order the product to be positive, therefore \(x>0\). So, from this statement, we cannot say whether \(0<x<1\) is true. Hope it's clear.
_________________
New to the Math Forum? Please read this: All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Current Student
Joined: 04 May 2012
Posts: 76
Location: Bangladesh
Concentration: Finance, Accounting
GPA: 3.86
WE: Analyst (Venture Capital)

Re: DS Algebra [#permalink]
Show Tags
20 Jul 2012, 10:06
Bunuel wrote: rxs0005 wrote: Is x between 0 and 1?
(1)  x < x^3 (2) x < x^2 Is \(0<x<1\)? (1) x<x^3 > \(x^3+x>0\) > \(x(x^2+1)>0\) > \(x>0\) (as x^2+1 is always positive). Not sufficient. (2) x<x^2 > \(x^2x>0\) > \(x(x1)>0\) > either \(x>1\) or \(x<0\), so the answer is NO. Sufficient. Answer: B. Dear Bunuel, if x is a negative integer, even then we can conclude that x < x^2 from B, how can we know that x cannot be a negative integer??



Math Expert
Joined: 02 Sep 2009
Posts: 39673

Re: DS Algebra [#permalink]
Show Tags
20 Jul 2012, 11:24
asifibaju wrote: Bunuel wrote: rxs0005 wrote: Is x between 0 and 1?
(1)  x < x^3 (2) x < x^2 Is \(0<x<1\)? (1) x<x^3 > \(x^3+x>0\) > \(x(x^2+1)>0\) > \(x>0\) (as x^2+1 is always positive). Not sufficient. (2) x<x^2 > \(x^2x>0\) > \(x(x1)>0\) > either \(x>1\) or \(x<0\), so the answer is NO. Sufficient. Answer: B. Dear Bunuel, if x is a negative integer, even then we can conclude that x < x^2 from B, how can we know that x cannot be a negative integer?? Not quite sure understand your question. We are asked: is \(0<x<1\)? From (2) we have that \(x>1\) or \(x<0\), which means that \(x\) could be any negative number (including integers) as well as any number greater than 1 . Hence the answer to the question whether \(0<x<1\) is NO.
_________________
New to the Math Forum? Please read this: All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
What are GMAT Club Tests? Extrahard Quant Tests with Brilliant Analytics



Current Student
Joined: 04 May 2012
Posts: 76
Location: Bangladesh
Concentration: Finance, Accounting
GPA: 3.86
WE: Analyst (Venture Capital)

Re: DS Algebra [#permalink]
Show Tags
20 Jul 2012, 11:54
oops !! i am really sorry !! Got it now.. I was out of my mind and asked such a silly question.. effect of a hectic day.. sorry again



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 15980

Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
24 Jan 2017, 16:04
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Intern
Joined: 01 Jun 2015
Posts: 1

Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
18 Jun 2017, 23:17
dear Bunuel
could you please explain the statement 2 solution in more detail. i followed till the eq x(x1) > 0..after it how are we moving to x<0 or X>1
Thanks



Math Expert
Joined: 02 Sep 2009
Posts: 39673

Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2 [#permalink]
Show Tags
19 Jun 2017, 03:59




Re: Is x between 0 and 1? (1)  x < x^3 (2) x < x^2
[#permalink]
19 Jun 2017, 03:59







