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 →

help with permutation problem!

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 100
Joined: Wed Jul 30, 2008 9:52 am
Thanked: 4 times
by ashish1354 » Tue Feb 17, 2009 10:54 pm
28. How many four-digit numbers that do not contain the digits 3 [color=red]or[/color] 6 are there?

28. How many four-digit numbers that do not contain the digits 3 [color=green]and[/color] 6 are there?

can someone explain the difference between the two questions?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 100
Joined: Wed Jul 30, 2008 9:52 am
Thanked: 4 times

sorrry guys !

by ashish1354 » Tue Feb 17, 2009 11:05 pm
Can someone please explain the difference between the following two problems?

How many four-digit numbers that do not contain the digits 3 or 6 are there?

and

How many four-digit numbers that do not contain the digits 3 and 6 are there?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 80
Joined: Mon Feb 02, 2009 6:36 am
Thanked: 10 times

Re: sorrry guys !

by billzhao » Tue Feb 17, 2009 11:37 pm
ashish1354 wrote:Can someone please explain the difference between the following two problems?

How many four-digit numbers that do not contain the digits 3 or 6 are there?

and

How many four-digit numbers that do not contain the digits 3 and 6 are there?

The number of 4-digit integers that do not contain 3 is 8*9^3
The number of 4-digit integers that do not contain 6 is 8*9^3
The number of 4-digit integers that do not contain 3 and 6 is 7*8^3


So The number of 4-digit integers that do not contain 3 and 6 is 7*8^3
The number of 4-digit integers that do not contain 3 or 6 is 8*9^3+8*9^3-7*8^3
Yiliang
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 353
Joined: Sat Jan 20, 2007 1:29 am
Location: Italy
Thanked: 7 times
GMAT Score:720

by mjjking » Wed Feb 18, 2009 2:13 am
Could you please explain why billzhao?
Beat The GMAT - 1st priority
Enter a top MBA program - 2nd priority
Loving my wife: MOST IMPORTANT OF ALL!

REAL THING 1 (AUG 2007): 680 (Q43, V40)
REAL THING 2 (APR 2009): 720 (Q47, V41)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 80
Joined: Mon Feb 02, 2009 6:36 am
Thanked: 10 times

by billzhao » Wed Feb 18, 2009 5:57 am
mjjking, I guess i need to explain the relationship of the three sets. I have drawn the graph for explanation.
Attachments
graph.gif
graph.gif
Yiliang
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 129
Joined: Mon Dec 15, 2008 11:43 pm
Location: Hyderabad
Thanked: 2 times

by naaga » Wed Feb 18, 2009 6:16 am
The number of 4-digit integers that do not contain 3 is 8*9^3
The number of 4-digit integers that do not contain 6 is 8*9^3
The number of 4-digit integers that do not contain 3 and 6 is 7*8^3


Billzhao , why did you take 8*9^3 actually it is 9 * 9 * 9 * 9

plz don't misunderstand me I am bit weak in this area

so, kindly make for me.....thankyou
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 80
Joined: Mon Feb 02, 2009 6:36 am
Thanked: 10 times

by billzhao » Fri Feb 20, 2009 5:00 am
naaga wrote:The number of 4-digit integers that do not contain 3 is 8*9^3
The number of 4-digit integers that do not contain 6 is 8*9^3
The number of 4-digit integers that do not contain 3 and 6 is 7*8^3


Billzhao , why did you take 8*9^3 actually it is 9 * 9 * 9 * 9

plz don't misunderstand me I am bit weak in this area

so, kindly make for me.....thankyou
Because the first digit cannot be "0"
Yiliang
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1