MBA Spotlight Virtual MBA Fair is Oct 13 – 21. Learn how to Register and Attend – it’s Free! New to GMAT Club? Watch this Video
close

It is currently 22 Oct 2020, 09:48
Register
GMAT Club Tests
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

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.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC
If r, s and t are consecutive integers, what is the greatest prime fac
6 posts Go to First Unread Post
Print view
NEW TOPIC
POST REPLY
Downloads
My Bookmarks
Reviews
SORT BY:
Date
Kudos
Tags :
Find Similar Topics 

Show Tags
Hide Tags

User avatar
V
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 67585
CAT Tests
Top Member of the Month
If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  07 Mar 2017, 10:54
1
Expert Reply
8
Bookmarks
00:00
A
B
C
D
E

Difficulty:

25% (medium)

Question Stats:

70% (01:10) correct 30% (01:22) wrong based on 207 sessions

Hide Show timer Statistics

If r, s and t are consecutive integers, what is the greatest prime factor of 3^r + 3^s + 3^t ?

A) 3
B) 5
C) 7
D) 11
E) 13
ShowHide Answer
Official Answer
Official Answer and Stats are available only to registered users. Register/Login.

_________________
New to the GMAT CLUB Forum?
Posting Rules: QUANTITATIVE | VERBAL. Guides and Resources: QUANTITATIVE | VERBAL | Ultimate GMAT Quantitative Megathread | All You Need for Quant

Questions' Banks and Collection:
PS: Standard deviation | Tough Problem Solving Questions With Solutions | Probability and Combinations Questions With Solutions | Tough and tricky exponents and roots questions | 12 Easy Pieces (or not?) | Bakers' Dozen | Algebra set | Mixed Questions | Fresh Meat
DS: DS Standard deviation | Inequalities | 700+ GMAT Data Sufficiency Questions With Explanations | Tough and tricky exponents and roots questions | The Discreet Charm of the DS | Devil's Dozen!!! | Number Properties set | New DS set
MIXED: GMAT Club's Complete Questions' Bank | SEVEN SAMURAI OF 2012 | Tricky questions from previous years. | Special Questions' Directory | Best Of The Best Of 2017 | The Best Of Quant of 2016 | 20 hardest and 20 best questions of 2015 | 15 best topics of 2015 | Seven Samurai of 2012 | GMAT Probability Questions

What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics
Signature Read More
avatar
S
quantumliner
Senior Manager
Senior Manager
Joined: 24 Apr 2016
Posts: 305
Re: If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  07 Mar 2017, 11:09
2
1
1
Bookmarks
Let R = x, S = x+1, T = x+2

3^r + 3^s + 3^t = 3^x + 3^(x+1) + 3^(x+2) = 3^x(1+3+9) = 3^x *13

Therefore greatest prime factor of 3^r + 3^s + 3^t is 13

Answer is E) 13
avatar
V
rohan2345
BSchool Forum Moderator
Joined: 29 Jan 2015
Posts: 1484
Location: India
WE:General Management (Consumer Products)
GMAT ToolKit User Reviews Badge
Re: If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  07 Mar 2017, 12:42
Let’s pick smart numbers.

Let r =0, let s= 1 and let t= 2

Hence the equation becomes 3^0+ 3^1 + 3 ^2

Which is equal to 1+3+9

= 13 = 13*1

Therefore the greatest prime factor is 13. Hence E.
avatar
S
SeregaP
Manager
Manager
Joined: 03 Jan 2017
Posts: 131
Re: If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  09 Mar 2017, 13:48
As they are consequative we can write it so: 3^r(1+3^1+3^2)=3^r*13
So answer is 13 (E)
User avatar
G
JeffTargetTestPrep
Target Test Prep Representative
Joined: 04 Mar 2011
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Posts: 2798
Re: If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  15 Mar 2017, 15:40
Expert Reply
Bunuel wrote:
If r, s and t are consecutive integers, what is the greatest prime factor of 3^r + 3^s + 3^t ?

A) 3
B) 5
C) 7
D) 11
E) 13


Let’s say r = 1, s = 2, and t = 3; then we have:

3^1 + 3^2 + 3^3 = 3^1(1 + 3 + 9) = 3(13)

Let’s say r = 2, s = 3, and t = 4; then we have:

3^2 + 3^3 + 3^4 = 3^2(1 + 3 + 9) = 3^2(13)

We see that regardless of the 3 consecutive positive integers we select, the largest prime will always be 13 since the other factor is always a power of 3.

Answer: E
_________________

★ ★ ★ ★ ★   250 REVIEWS

5-STAR RATED ONLINE GMAT QUANT SELF STUDY COURSE

NOW WITH GMAT VERBAL (BETA)

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

Signature Read More
User avatar
bumpbot
Non-Human User
Joined: 09 Sep 2013
Posts: 16195
Re: If r, s and t are consecutive integers, what is the greatest prime fac [#permalink] New post  29 Sep 2020, 22:55
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
Signature Read More
GMAT Club Bot
gmatclubot
[#permalink]
NEW TOPIC
POST REPLY
Downloads
My Bookmarks
Reviews
Moderators:
chetan2u
Math Expert
8941 posts
Bunuel
Math Expert
67584 posts
VeritasKarishma
Veritas Prep GMAT Instructor
11125 posts
yashikaaggarwal
Senior Moderator - Masters Forum
2147 posts
generis
Senior SC Moderator
4212 posts
Feedback

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions