Last visit was: 03 May 2026, 05:18 It is currently 03 May 2026, 05:18
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
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 03 May 2026
Posts: 110,019
Own Kudos:
Given Kudos: 105,993
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,019
Kudos: 812,636
 [10]
Kudos
Add Kudos
10
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 03 May 2026
Posts: 110,019
Own Kudos:
812,636
 [7]
Given Kudos: 105,993
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,019
Kudos: 812,636
 [7]
2
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
General Discussion
User avatar
leve
Joined: 16 Nov 2015
Last visit: 26 May 2016
Posts: 13
Own Kudos:
16
 [7]
Given Kudos: 64
Posts: 13
Kudos: 16
 [7]
6
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
PrayasT
Joined: 26 Feb 2018
Last visit: 22 Dec 2020
Posts: 41
Own Kudos:
59
 [1]
Given Kudos: 43
Location: India
GMAT 1: 640 Q45 V34
GPA: 3.9
WE:Web Development (Computer Software)
GMAT 1: 640 Q45 V34
Posts: 41
Kudos: 59
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I agree with explanation.
User avatar
RenanBragion
User avatar
Current Student
Joined: 01 Jun 2020
Last visit: 14 Oct 2025
Posts: 130
Own Kudos:
Given Kudos: 12
Location: Brazil
GMAT 1: 760 Q48 V46
Products:
GMAT 1: 760 Q48 V46
Posts: 130
Kudos: 14
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I agree with explanation.
User avatar
coreyander
User avatar
Retired Moderator
Joined: 31 May 2020
Last visit: 11 Jun 2024
Posts: 167
Own Kudos:
Given Kudos: 47
Location: India
Posts: 167
Kudos: 1,169
Kudos
Add Kudos
Bookmarks
Bookmark this Post
LOGICAL METHOD:

|a-b|=2 --> Distance between A & B is 2.

|b-c|=2 --> Distance between B & C is 2.

|a-c|? --> What is the distance between A & C?

The above requirements can be achieved in the below two following ways... (It can also be achieved by using the mirror image of the below, but will get the same result)
Attachment:
Figure 1.jpg
Figure 1.jpg [ 11.15 KiB | Viewed 9282 times ]

As we can infer from the diagram, distance between a & c can be 4 or 0..

1) a<b<c
Only the first figure satisfies this condition. Thus, |a-c|=4... (In 2nd figure, we have a=c and not a<c)
Sufficient

2) \(c-a>c-b\)
Simplifying we get \(-a > -b\) --> \(a<b\)
In both the figures, a is less than b... But |a-c|= 4 or 0..
Hence, insufficient.

Answer (A)
User avatar
coreyander
User avatar
Retired Moderator
Joined: 31 May 2020
Last visit: 11 Jun 2024
Posts: 167
Own Kudos:
Given Kudos: 47
Location: India
Posts: 167
Kudos: 1,169
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ALGEBRAIC APPROACH:

Things to know:

#1:
---------> |a| = a, when a>=0
---------> |a| = -a, when a<0

#2:
|x|=|y|

Case 1: When x>0 & y>0
x=y
Case 2: When x>0 & y<0
x=-y
Case 3: When x<0 & y>0
-x=y
Case 4: When x<0 & y<0
-x = -y

Case 1 & 3 are same equations. Case 2 & 4 are same equations. Thus, |x|=|y| can give one of the below two equations.
1) x = y
2) x = -y

Back to the question:

Similarly, |a-b|=|b-c| will yield

Case 1) a-b = b-c---------------> a+c=2b-----------> c =2b-a
Thus, |a-c|= |a-(2b-a)|=|2a-2b|=|2(a-b)|=2|a-b|=2*2=4.............(Question stem gives |a-b|=2)
|a-c|=4

Case 2) a-b = c-b
Thus, a=c----> a-c=0

Statement 1) a<b<c
Thus, \(a \neq c\) since a<c... Case 2 is not applicable.
Case 1 it is... |a-c|=4
Sufficient.

Statement 2) c-a>c-b
Thus, a<b....
This information doesn't give us any information to eliminate one of the above cases.
Insufficient.

Answer A
User avatar
coreyander
User avatar
Retired Moderator
Joined: 31 May 2020
Last visit: 11 Jun 2024
Posts: 167
Own Kudos:
Given Kudos: 47
Location: India
Posts: 167
Kudos: 1,169
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ALGEBRAIC APPROACH 2:

Simplifying |a-b|=|b-c|

\((a-b)^2=(b-c)^2\)
\((a+c)(a-c)=2b(a-c)\)

Don't be too hasty and cancel (a-c) on both sides..
What if a=c.... i.e a-c=0?
You can't divide by zero..

Thus, LHS = RHS if
case 1) a-c = 0 ---> a=c
Case 2) \(a-c \neq 0\), in which case we can cancel (a-c) on both sides, and we get a+c = 2b.... c=2b-a

case 1 gives |a-c|=0
Case 2 gives
|a-c|=|a-(2b-a)|=|2a-2b|=|2(a-b)|=2|a-b|=2*2=4.............(Question stem gives |a-b|=2)

Statement 1) a<b<c
Thus, a≠c since a<c... Case 1 is not applicable.
Case 2 it is... |a-c|=4
Sufficient.

Statement 2) c-a>c-b
Thus, a<b....
This information doesn't give us any information to eliminate one of the above cases.
Insufficient.

Answer A
avatar
Laksh47
Joined: 01 Mar 2020
Last visit: 18 Apr 2021
Posts: 25
Own Kudos:
Given Kudos: 65
Posts: 25
Kudos: 4
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi Bunuel,

Should we consider a =c as a possibility in this question? Or should we consider a and c as two points with different values?

Looking forward to your response. Thanks in advance!!
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 03 May 2026
Posts: 110,019
Own Kudos:
Given Kudos: 105,993
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,019
Kudos: 812,636
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Laksh47
Hi Bunuel,

Should we consider a =c as a possibility in this question? Or should we consider a and c as two points with different values?

Looking forward to your response. Thanks in advance!!

Unless it is explicitly stated otherwise, different variables CAN represent the same number. So, from the stem a = c is certainly possible. When considering the first statement alone, it's no longer possible because (1) says a < b < c. When considering the second statement alone, it's again passible that a = c.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 03 May 2026
Posts: 110,019
Own Kudos:
Given Kudos: 105,993
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,019
Kudos: 812,636
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I have edited the question and the solution by adding more details to enhance its clarity. I hope it is now easier to understand.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 03 May 2026
Posts: 110,019
Own Kudos:
Given Kudos: 105,993
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,019
Kudos: 812,636
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Similar PS question to practice:
https://gmatclub.com/forum/m41-428842.html
Moderators:
Math Expert
110019 posts
Founder
43197 posts