BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Permutations

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 6
Joined: Mon Aug 02, 2010 3:51 am
by ruthm_24 » Sat Oct 02, 2010 10:24 am
All of the stocks on the over-the-counter market are designated by either a 4-letter or a 5-letter code that is created by using the 26 letters of the alphabet. Which of the following gives the maximum number of different stocks that can be designated with these codes?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Senior | Next Rank: 100 Posts
Posts: 81
Joined: Sat Aug 08, 2009 1:16 pm
Thanked: 2 times

by Arcane66 » Sat Oct 02, 2010 10:58 am
Hmm, is the answer 8,252,400? I got this by using the permutation formula twice. 26!/(26-4)! + 26!/(26-5)!. I
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Newbie | Next Rank: 10 Posts
Posts: 6
Joined: Mon Aug 02, 2010 3:51 am

by ruthm_24 » Sat Oct 02, 2010 11:09 am
Sorry, forgot to post that the answer is [spoiler]27(26^4)[/spoiler].
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 174
Joined: Fri Apr 02, 2010 3:41 pmFollowed by: 1 member
Thanked: 6 times

by sanabk » Mon Oct 04, 2010 3:49 pm
4-letter code
=26 x 26 x 26 x 26
=(26)^4

5-letter code
=26 x 26 x 26 x 26 x 26
=(26)^5

Total=(26)^4 + (26)^5
= (26)^4 + 26 x (26)^4
=(26)^4 [1+26]
=27 x (26)^4
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 156
Joined: Sat Sep 04, 2010 2:27 am
Location: Leeds,UK
Thanked: 1 times

by lokesh r » Tue Oct 05, 2010 7:15 am
sanabk wrote:4-letter code
=26 x 26 x 26 x 26
=(26)^4

5-letter code
=26 x 26 x 26 x 26 x 26
=(26)^5

Total=(26)^4 + (26)^5
= (26)^4 + 26 x (26)^4
=(26)^4 [1+26]
=27 x (26)^4
Hey i think u are assuming repitition allowed, but question does not explicitly mention that repitition is allowed.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1255
Joined: Fri Nov 07, 2008 2:08 pmFollowed by: 90 members
Location: St. Louis
Thanked: 312 times

by Tani » Tue Oct 05, 2010 10:58 am
UNless the questions tells you that you cannot repeat a letter, then repetition is possible. You can't assume an unstated restriction.
Tani Wolff
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1