Last visit was: 15 May 2025, 18:55 It is currently 15 May 2025, 18:55
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
carcass
User avatar
Board of Directors
Joined: 01 Sep 2010
Last visit: 15 May 2025
Posts: 4,642
Own Kudos:
35,730
 [79]
Given Kudos: 4,759
Products:
Posts: 4,642
Kudos: 35,730
 [79]
10
Kudos
Add Kudos
69
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 15 May 2025
Posts: 101,447
Own Kudos:
Given Kudos: 93,517
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 101,447
Kudos: 724,507
 [21]
15
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 15 May 2025
Posts: 101,447
Own Kudos:
724,507
 [7]
Given Kudos: 93,517
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 101,447
Kudos: 724,507
 [7]
6
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
General Discussion
User avatar
carcass
User avatar
Board of Directors
Joined: 01 Sep 2010
Last visit: 15 May 2025
Posts: 4,642
Own Kudos:
35,730
 [1]
Given Kudos: 4,759
Products:
Posts: 4,642
Kudos: 35,730
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I suppose that you have put in red my logic on stat 1 because not so clear.

Stat (1) : x > 1 or -x > 1.........x < -1

Stat (2) : x < x or -x > x.........x < -x

This is the logic that conduct me to say that the 2 stats are insufficient. I don't understand completely why in the 2 one |x| > x ........ x is < 0 ??'


I also read the topic that you suggested; your third reply is very helpful but the doubt remain on stat ( 2)

Thanks
User avatar
carcass
User avatar
Board of Directors
Joined: 01 Sep 2010
Last visit: 15 May 2025
Posts: 4,642
Own Kudos:
Given Kudos: 4,759
Products:
Posts: 4,642
Kudos: 35,730
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Thank you a lot.

Now right away I'll read absolute value chapter.
User avatar
WholeLottaLove
Joined: 13 May 2013
Last visit: 13 Jan 2014
Posts: 305
Own Kudos:
612
 [3]
Given Kudos: 134
Posts: 305
Kudos: 612
 [3]
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
If x is different from 0, is |x| < 1 ?
x≠0, is -1<x<1?

(1) x |x| < x
For this to hold true: 0<x<1 or x<-1

0<x<1
1/2 * |1/2| < 1/2
1/4 < 1/2 Valid

x<-1
-2 * |-2| < -2
-4 < -2 Valid

x could be between 0 and 1 or it could be less than -1.
INSUFFICIENT

(2) |x| > x
|x| is by definition ≥0 so for |x| to be greater than x, x must be negative. Depending on the value of -x, it may or may not satisfy the inequality.
INSUFFICIENT

1+2) 0<x<1 or x<-1 and x is negative. The only intersection is when x<-1 and "x is negative" meaning x<-1 and the inequality in the stem holds true.
SUFFICIENT

(C)
avatar
pmsigns
Joined: 14 Jul 2009
Last visit: 26 Sep 2024
Posts: 7
Own Kudos:
Given Kudos: 6
Posts: 7
Kudos: 3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
i solved it in the following way.. what am i doing wrong ?

for x|x|<x

a. x>0: xx<x -> x<1 i.e. 0<x<1
b. x<0: -xx<x -> -x<1 -> x>-1 which is wrong.

ln another problem i solved x/|x| similarly, and got the correct answer .

for x/|x|< x

x>0: x/x<x -> 1<x
x<0: x/-x<x ->-1<x<0


i am confused ..
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 15 May 2025
Posts: 101,447
Own Kudos:
724,507
 [1]
Given Kudos: 93,517
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 101,447
Kudos: 724,507
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
pmsigns
i solved it in the following way.. what am i doing wrong ?

for x|x|<x

a. x>0: xx<x -> x<1 i.e. 0<x<1
b. x<0: -xx<x -> -x<1 -> x>-1 which is wrong.

i am confused ..

For (b) when x<0 you have: -x*x < x --> divie by negative x and flip the sign: -x>1 --> x<-1.
User avatar
him1985
Joined: 20 Jan 2014
Last visit: 12 Jul 2018
Posts: 108
Own Kudos:
199
 [2]
Given Kudos: 120
Location: India
Concentration: Technology, Marketing
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
If x is different from 0, is |x| < 1 ?

(1) x*|x| < x

(2) |x| > x
_____________________

1) x*|x| < x : on first look it seems to be sufficient, Divide by X from both side and we will get the answer, But this is the catch here.
We only know that X != 0 . X can e negative as well and if X is negative then it will reverse the sign. So we get two conditions here. X +ve and x-ve

For X +ve = divide by X = |X| <1
For X -ve = divide by -X = |X| >1
So not sufficient.

2) |x| > x : It says that X is -ve. Only in this scenerio |X| can be greater than X. This is also not sufficient.

Now Lets take ! and 2 both
We know from 2 that X is -ve so from 1 we get |X| >1. Answer is no |X| is not less than 1.
So C is sufficient
avatar
shiying
Joined: 13 Dec 2017
Last visit: 06 Sep 2018
Posts: 3
Given Kudos: 85
Posts: 3
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
carcass
I suppose that you have put in red my logic on stat 1 because not so clear.

Stat (1) : x > 1 or -x > 1.........x < -1

Stat (2) : x < x or -x > x.........x < -x

This is the logic that conduct me to say that the 2 stats are insufficient. I don't understand completely why in the 2 one |x| > x ........ x is < 0 ??'


I also read the topic that you suggested; your third reply is very helpful but the doubt remain on stat ( 2)

Thanks
OK. First of all: I marked "|x|<1" in red for (1), because you don't get that |x| < 1 from this statement. If it were so then then you'd have an YES answer right away (as the question asks exactly about the same thing "is |x|<1")

Next, "is \(|x|<1\)?" means "is \(-1<x<1\)?"

(1) x*|x|<x holds true in two cases for \(x<-1\) and \(0<x<1\):
-----(-1)----(0)----(1)----
So as you can see this one is not sufficient to answer the question.

Hope it's clear.

Hi Bunuel, can x also be x>-1 for Statement 1? Coz when I sub in the values of (-1/2) or (-1/4), x satisfies the equation. But on your number line it is in black, which indicates x>-1 does not hold true. Please kindly enlighten me.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 15 May 2025
Posts: 101,447
Own Kudos:
Given Kudos: 93,517
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 101,447
Kudos: 724,507
Kudos
Add Kudos
Bookmarks
Bookmark this Post
shiying
Bunuel
carcass
I suppose that you have put in red my logic on stat 1 because not so clear.

Stat (1) : x > 1 or -x > 1.........x < -1

Stat (2) : x < x or -x > x.........x < -x

This is the logic that conduct me to say that the 2 stats are insufficient. I don't understand completely why in the 2 one |x| > x ........ x is < 0 ??'


I also read the topic that you suggested; your third reply is very helpful but the doubt remain on stat ( 2)

Thanks
OK. First of all: I marked "|x|<1" in red for (1), because you don't get that |x| < 1 from this statement. If it were so then then you'd have an YES answer right away (as the question asks exactly about the same thing "is |x|<1")

Next, "is \(|x|<1\)?" means "is \(-1<x<1\)?"

(1) x*|x|<x holds true in two cases for \(x<-1\) and \(0<x<1\):
-----(-1)----(0)----(1)----
So as you can see this one is not sufficient to answer the question.

Hope it's clear.

Hi Bunuel, can x also be x>-1 for Statement 1? Coz when I sub in the values of (-1/2) or (-1/4), x satisfies the equation. But on your number line it is in black, which indicates x>-1 does not hold true. Please kindly enlighten me.

Neither of these values satisfies x*|x| < x.

If x = -1/2, then (x*|x| = -1/4) > -1/2 NOT <.
User avatar
Sabby
Joined: 17 Jun 2018
Last visit: 02 May 2025
Posts: 84
Own Kudos:
Given Kudos: 397
Location: France
GPA: 3.85
Posts: 84
Kudos: 98
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi,

I like to use smart numbers for this type of questions otherwise I feel completely lost.

Let x be : -2 or -1/2 or 1/2 or 2

1) cases where x*Ixl<x :

With x=-2
-2*l2l<-2 ==> -4<-2 and here l2l>1, is lxl<1? NO

With x= 1/2
1/2*1/2<1/2 ==> 1/4<1/2 and here l1/2l<1, is lxl<1? YES

we have a yes and no so it's insufficient

2) Cases where lxl>x

When x=-2
l2l>-2 ==> is lxl<1? NO

When x=-1/2
l1/2l>-1/2 ==> is lxl<1? YES

We have a yes and no so it's insufficient

1)+2) We have only one value that is consistent with the two statements and it's -2. Therefore, is lxl<1? the answer is NO.

Answer C)
User avatar
GMATGuruNY
Joined: 04 Aug 2010
Last visit: 15 May 2025
Posts: 1,346
Own Kudos:
Given Kudos: 9
Schools:Dartmouth College
Expert
Expert reply
Posts: 1,346
Kudos: 3,591
Kudos
Add Kudos
Bookmarks
Bookmark this Post
carcass
If x is different from 0, is |x| < 1 ?

(1) x*|x| < x

(2) |x| > x

Statement 1:
CRITICAL POINTS occur when the two sides of an inequality are EQUAL or when the inequality is UNDEFINED.
\(x|x|=x\) when x=-1, x=0 or x=1

The critical points are x=-1, x=0 and x=1, implying the following number line:
..........-1..........0..........1..........
To determine which ranges for x are valid, test one value to the left and one value to the right of each critical point.
If we test x=-2, x=-1/2, x=1/2 and x=2, only x=-2 and x=1/2 satisfy \(x|x|<x\), implying that the valid ranges are x<-1 and 0<x<1.

Case 1: x<-1
In this case, |x|>1, so the answer to the question stem is NO.
Case 2: 0<x<1
In this case, |x|<1, so the answer to the question stem is YES.
INSUFFICIENT.

Statement 2:
|x|>x for all negative values of x.
If x=-1/2, then |x|<1, so the answer to the question stem is YES.
If x=-2, then |x|>1, so the answer to the question stem is NO.
INSUFFICIENT.

Statements combined:
Only Case 1 satisfies both statements.
In Case 1, the answer to the question stem is NO.
SUFFICIENT.

User avatar
TBT
Joined: 09 Aug 2020
Last visit: 26 Nov 2023
Posts: 310
Own Kudos:
Given Kudos: 494
Location: India
Concentration: Marketing, General Management
Posts: 310
Kudos: 428
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Got to learn so much from this question! I was making mistake while defining the range. This brushes up your concept of inequality!
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 36,852
Own Kudos:
Posts: 36,852
Kudos: 983
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderator:
Math Expert
101447 posts