Last visit was: 25 Apr 2026, 04:08 It is currently 25 Apr 2026, 04:08
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
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,777
Own Kudos:
13,048
 [6]
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,777
Kudos: 13,048
 [6]
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
User avatar
peachfuzz
Joined: 28 Feb 2014
Last visit: 27 Jan 2018
Posts: 268
Own Kudos:
369
 [2]
Given Kudos: 132
Location: United States
Concentration: Strategy, General Management
Products:
Posts: 268
Kudos: 369
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
ENGRTOMBA2018
Joined: 20 Mar 2014
Last visit: 01 Dec 2021
Posts: 2,319
Own Kudos:
3,890
 [2]
Given Kudos: 816
Concentration: Finance, Strategy
GMAT 1: 750 Q49 V44
GPA: 3.7
WE:Engineering (Aerospace and Defense)
Products:
GMAT 1: 750 Q49 V44
Posts: 2,319
Kudos: 3,890
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,777
Own Kudos:
13,048
 [1]
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,777
Kudos: 13,048
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
EMPOWERgmatRichC
QUANT 4-PACK SERIES Problem Solving Pack 4 Question 3 If a, b and c are consecutive...

If a, b and c are consecutive positive integers and a < b < c, then what is the minimum possible value of

\(3^{2bc}\) / \(3^{2ab}\)

A) 81
B) 2,187
C) 3,300
D) 6,561
E) 19,683

Hi All,

To start, the answer choices to this question are rather 'spread out', so we might be able to use that spread to our advantage (and avoid some calculations).

We're told that a, b and c are consecutive positive integers and a < b < c. We're asked for the MINIMUM value of \(3^{2bc}\) / \(3^{2ab}\)...

Since the prompt asks for the MINIMUM value, it's likely that we'll have to make the 3 variables as small as possible, but we'll have to check to make sure that that's what is required to get to the correct answer. The smallest 3 numbers that 'fit' are...

a = 1
b = 2
c = 3

This makes the calculation...

\(3^{12}\) / \(3^{4}\) = \(3^{8}\)

\(3^{8}\)= \(9^{4}\) = \(81^{2}\) = ABOUT \(80^{2}\) = ABOUT 6400, so the answer appears to be D. We just need to confirm that that's the case....

IF....
a = 2
b = 3
c = 4

This makes the calculation...

\(3^{24}\) / \(3^{12}\) = \(3^{12}\)

\(3^{12}\) is clearly bigger than \(3^{8}\), meaning that increasing the values of a, b and c will lead to a LARGER end result. This proves that D is actually the smallest possible result.

Final Answer:
GMAT assassins aren't born, they're made,
Rich
User avatar
mvictor
User avatar
Board of Directors
Joined: 17 Jul 2014
Last visit: 14 Jul 2021
Posts: 2,118
Own Kudos:
1,277
 [1]
Given Kudos: 236
Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30
GPA: 3.92
WE:General Management (Transportation)
Products:
GMAT 1: 650 Q49 V30
Posts: 2,118
Kudos: 1,277
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
since a, b, and c are consecutive integers, and positive: we can rewrite the fraction as

3^[2bc-2ab] or
3^[2(bc-ab)] or
3^[2(b(c-a))]

since a,b,c are consecutive integers, c-a is always = 2 regardless of the values they take.

now, we are left with 3^4b
to minimize the value, we need to take the minimal value of b, while taking into consideration that a,b,c - must be positive and numbers are consecutive numbers.
minimal value of b is 2.

now, 3^8 = 9^4 or 81^2.
don't need to solve for the exact value. the correct answer choice must have 1 at the end, and since A cannot be the answer, the only correct answer that it can be is D.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,976
Own Kudos:
Posts: 38,976
Kudos: 1,117
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Math Expert
109822 posts
Tuck School Moderator
853 posts