Last visit was: 21 Apr 2026, 16:41 It is currently 21 Apr 2026, 16:41
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: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
 [11]
3
Kudos
Add Kudos
8
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
810,465
 [4]
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
 [4]
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
Josvit
Joined: 19 Apr 2023
Last visit: 22 Aug 2024
Posts: 18
Own Kudos:
17
 [2]
Given Kudos: 9
Posts: 18
Kudos: 17
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
karansinghania
Joined: 04 Sep 2020
Last visit: 25 Dec 2024
Posts: 4
Given Kudos: 3
Posts: 4
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
Official Solution:


The function \(max(a, b)\) returns the largest, and \(min(a, b)\) returns the smallest value among the given numbers \(a\) and \(b\). If \(a\) and \(b\) are distinct numbers, which of the following must be true?

I. \(max(a, b) + min(a, b) > 0\)

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)



A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III


Let's evaluate each option

I. \(max(a, b) + min(a, b) > 0\)

If we assume \(a > b\), then the above expression becomes \(a + b > 0\). However, this is not necessarily true, as the fact that one number is greater than another does not guarantee a positive sum. The same result occurs if we assume \(a < b\). Therefore, this option is not always true.

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(max(a, b)\), equals \(a\). Since in this case, \(|a - b| = a-b\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b + a - b}{2}=a\). Thus, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(max(a, b)\), equals \(b\). Since in this case, \(|a - b| = -(a-b)\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Again, for this case, LHS = RHS.

Hence, this option must be true.

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(min(a, b)\), equals \(b\). In this case, \(|a - b| = a-b\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Therefore, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(min(a, b)\), equals \(a\). Here, \(|a - b| = -(a-b)\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b + (a - b)}{2}=a\). So, once again, for this case, LHS = RHS.

Thus, this option must NOT be true.

Therefore, only option II is always true!


Answer: B
­

You proved III to be true in both cases but said it must NOT be true, why?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
Kudos
Add Kudos
Bookmarks
Bookmark this Post
karansinghania

Bunuel
Official Solution:


The function \(max(a, b)\) returns the largest, and \(min(a, b)\) returns the smallest value among the given numbers \(a\) and \(b\). If \(a\) and \(b\) are distinct numbers, which of the following must be true?

I. \(max(a, b) + min(a, b) > 0\)

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)



A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III


Let's evaluate each option

I. \(max(a, b) + min(a, b) > 0\)

If we assume \(a > b\), then the above expression becomes \(a + b > 0\). However, this is not necessarily true, as the fact that one number is greater than another does not guarantee a positive sum. The same result occurs if we assume \(a < b\). Therefore, this option is not always true.

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(max(a, b)\), equals \(a\). Since in this case, \(|a - b| = a-b\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b + a - b}{2}=a\). Thus, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(max(a, b)\), equals \(b\). Since in this case, \(|a - b| = -(a-b)\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Again, for this case, LHS = RHS.

Hence, this option must be true.

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(min(a, b)\), equals \(b\). In this case, \(|a - b| = a-b\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Therefore, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(min(a, b)\), equals \(a\). Here, \(|a - b| = -(a-b)\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b + (a - b)}{2}=a\). So, once again, for this case, LHS = RHS.

Thus, this option must NOT be true.

Therefore, only option II is always true!


Answer: B
­

You proved III to be true in both cases but said it must NOT be true, why?
­

III says \(min(a, b) < \frac{a + b - |a - b|}{2}\), while we got that \(min(a, b) = \frac{a + b - |a - b|}{2}\). Thus, this option must NOT be true.­
avatar
odd_major
Joined: 17 Dec 2023
Last visit: 17 Jun 2025
Posts: 58
Own Kudos:
Given Kudos: 65
Location: India
GMAT Focus 1: 715 Q90 V88 DI79
GPA: 8.1/10
GMAT Focus 1: 715 Q90 V88 DI79
Posts: 58
Kudos: 23
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question.
User avatar
isaisrz
Joined: 06 Oct 2024
Last visit: 26 Feb 2025
Posts: 4
Own Kudos:
Posts: 4
Kudos: 1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I don't agree with the explanation. this does not seem right, LHS does not equal RHS, does it ?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
Kudos
Add Kudos
Bookmarks
Bookmark this Post
isaisrz

Bunuel
Official Solution:


The function \(max(a, b)\) returns the largest, and \(min(a, b)\) returns the smallest value among the given numbers \(a\) and \(b\). If \(a\) and \(b\) are distinct numbers, which of the following must be true?

I. \(max(a, b) + min(a, b) > 0\)

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)


A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III


Let's evaluate each option

I. \(max(a, b) + min(a, b) > 0\)

If we assume \(a > b\), then the above expression becomes \(a + b > 0\). However, this is not necessarily true, as the fact that one number is greater than another does not guarantee a positive sum. The same result occurs if we assume \(a < b\). Therefore, this option is not always true.

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(max(a, b)\), equals \(a\). Since in this case, \(|a - b| = a-b\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b + a - b}{2}=a\). Thus, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(max(a, b)\), equals \(b\). Since in this case, \(|a - b| = -(a-b)\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Again, for this case, LHS = RHS.

Hence, this option must be true.

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(min(a, b)\), equals \(b\). In this case, \(|a - b| = a-b\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Therefore, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(min(a, b)\), equals \(a\). Here, \(|a - b| = -(a-b)\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b + (a - b)}{2}=a\). So, once again, for this case, LHS = RHS.

Thus, this option must NOT be true.

Therefore, only option II is always true!


Answer: B
I think this is a high-quality question and I don't agree with the explanation. this does not seem right, LHS does not equal RHS, does it ?

The question is 100% correct.

For example, consider a = 2 and b = 1, then:

• max(a, b) = max(2, 1) = 2.

• \(\frac{a + b + |a - b|}{2}= \frac{2 + 1 + |2 - 1|}{2}= \frac{3 + |1|}{2}= 2 \)

As you can see \(max(a, b) = \frac{a + b + |a - b|}{2}\).
User avatar
HRKT
Joined: 02 Jul 2024
Last visit: 23 Dec 2025
Posts: 7
Given Kudos: 2
Posts: 7
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I don’t quite agree with the solution. In 2 and 3 both LHS = RHS Still 3 is not right
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
Kudos
Add Kudos
Bookmarks
Bookmark this Post
HRKT
I don’t quite agree with the solution. In 2 and 3 both LHS = RHS Still 3 is not right

III says \(min(a, b) < \frac{a + b - |a - b|}{2}\), while we got that \(min(a, b) = \frac{a + b - |a - b|}{2}\). Thus, this option must NOT be true.­
User avatar
ninja_in_progress
Joined: 12 Jun 2023
Last visit: 17 Mar 2026
Posts: 11
Own Kudos:
Given Kudos: 77
Posts: 11
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
For II,
If a = -7 and b = 2

Max(a,b) = 2

a+b+|a-b|/2 = (-7+2+5)/2
= 0

Hence this condition fails, please correct if I am missing any assumptions here.
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
810,465
 [1]
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ninja_in_progress
For II,
If a = -7 and b = 2

Max(a,b) = 2

a+b+|a-b|/2 = (-7+2+5)/2
= 0

Hence this condition fails, please correct if I am missing any assumptions here.

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

If a = -7 and b = 2, then:

  • max(a, b) = max(-7, 2) = 2.
  • \(\frac{a + b + |a - b|}{2}= \frac{-7 + 2 + |-7 - 2|}{2}= \frac{-5 + |-9|}{2}= \frac{-5 + 9}{2}=2 \)

If a general proof shows that something always holds, trying to disprove it with specific numbers means the logic wasn’t fully understood. It’s better to go back and review the reasoning behind the proof.
User avatar
shaliny
Joined: 30 Oct 2023
Last visit: 21 Apr 2026
Posts: 120
Own Kudos:
Given Kudos: 980
Products:
Posts: 120
Kudos: 26
Kudos
Add Kudos
Bookmarks
Bookmark this Post
actually i am not getting this question, max a,b and min a,b...please help me to understand..
Bunuel
Official Solution:


The function \(max(a, b)\) returns the largest, and \(min(a, b)\) returns the smallest value among the given numbers \(a\) and \(b\). If \(a\) and \(b\) are distinct numbers, which of the following must be true?

I. \(max(a, b) + min(a, b) > 0\)

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)


A. I only
B. II only
C. III only
D. I and II only
E. I, II, and III


Let's evaluate each option

I. \(max(a, b) + min(a, b) > 0\)

If we assume \(a > b\), then the above expression becomes \(a + b > 0\). However, this is not necessarily true, as the fact that one number is greater than another does not guarantee a positive sum. The same result occurs if we assume \(a < b\). Therefore, this option is not always true.

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(max(a, b)\), equals \(a\). Since in this case, \(|a - b| = a-b\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b + a - b}{2}=a\). Thus, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(max(a, b)\), equals \(b\). Since in this case, \(|a - b| = -(a-b)\), the right-hand side, \(\frac{a + b + |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Again, for this case, LHS = RHS.

Hence, this option must be true.

III. \(min(a, b) < \frac{a + b - |a - b|}{2}\)

If \(a > b\), then the left-hand side, \(min(a, b)\), equals \(b\). In this case, \(|a - b| = a-b\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b - (a - b)}{2}=b\). Therefore, for this case, LHS = RHS.

If \(a < b\), then the left-hand side, \(min(a, b)\), equals \(a\). Here, \(|a - b| = -(a-b)\), and the right-hand side, \(\frac{a + b - |a - b|}{2}\), equals \(\frac{a + b + (a - b)}{2}=a\). So, once again, for this case, LHS = RHS.

Thus, this option must NOT be true.

Therefore, only option II is always true!


Answer: B
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
810,465
 [1]
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
shaliny
actually i am not getting this question, max a,b and min a,b...please help me to understand..


max(a, b) means the larger of the two numbers, and min(a, b) means the smaller. For example:

If a = 5 and b = 2, then max(a, b) = 5 and min(a, b) = 2.

If a = -3 and b = 7, then max(a, b) = 7 and min(a, b) = -3.
User avatar
Dream009
Joined: 05 Nov 2024
Last visit: 13 Mar 2026
Posts: 276
Own Kudos:
Given Kudos: 60
Location: India
Concentration: Strategy, Leadership
GMAT Focus 1: 615 Q82 V79 DI80
GRE 1: Q30 V50
GPA: 84
WE:General Management (Consulting)
Products:
GMAT Focus 1: 615 Q82 V79 DI80
GRE 1: Q30 V50
Posts: 276
Kudos: 98
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Check your math this actually results in 2.

(-7+2+9)/2 = 2 =max
ninja_in_progress
For II,
If a = -7 and b = 2

Max(a,b) = 2

a+b+|a-b|/2 = (-7+2+5)/2
= 0

Hence this condition fails, please correct if I am missing any assumptions here.
User avatar
Shrusti1905
Joined: 03 Jan 2022
Last visit: 08 Mar 2026
Posts: 1
Given Kudos: 2
Location: India
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I don’t quite agree with the solution. In case we a and b both are negative numbers then the solution does not hold true correct?
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Shrusti1905
I don’t quite agree with the solution. In case we a and b both are negative numbers then the solution does not hold true correct?

You are wrong!

II. \(max(a, b) = \frac{a + b + |a - b|}{2}\)

For example, if a = -1 and b = -2, then

\(max(-1, -2) = -1\)

\(\frac{-1 + (-2) + |(-1) - (-2)|}{2}= \frac{-3 +1}{2}= -1\)

The same result.
User avatar
f3rn4nd44m0r1m
Joined: 21 Aug 2024
Last visit: 06 Apr 2026
Posts: 47
Own Kudos:
Given Kudos: 292
Location: Brazil
Concentration: Entrepreneurship, Organizational Behavior
GMAT Focus 1: 605 Q77 V81 DI82
GPA: 8.5
WE:Project Management (Non-Profit)
Products:
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I like the solution - it’s helpful.
User avatar
Archisha14
Joined: 13 Dec 2025
Last visit: 16 Feb 2026
Posts: 2
Given Kudos: 9
Posts: 2
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I DIDNT UNDERSTAND WHAT CONCEPT IS BEINB APPLIED HERE
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
Given Kudos: 105,800
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,728
Kudos: 810,465
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Archisha14
I DIDNT UNDERSTAND WHAT CONCEPT IS BEINB APPLIED HERE
The question is fairly straightforward once you understand it. It tests whether you understand how max and min behave for two distinct numbers and how to verify “must be true” statements. What exactly is unclear in the question or the solution?

P.S. Please avoid using all caps when posting on a forum.
Moderators:
Math Expert
109728 posts
Founder
43149 posts