How many different five-digit numbers can be formed from the set of seven numbers {1,2,3,4,5,6,7} if

Parik

wrote...

Posts: 22

Rep:

9 years ago

How many different five-digit numbers can be formed from the set of seven numbers {1,2,3,4,5,6,7} if

19.   Simplify:
a)   23! /20!
b)   (n=2)! /(n+2)n!
c)   Solve for n:
(n+2)!/(n)! = 110

20.   How many different five-digit numbers can be formed from the set of seven numbers {1,2,3,4,5,6,7} if
a)   Repetition is allowed?
b)   Repetition is not allowed
c)   Repetition is allowed and the third digit must be different from the second digit?
Show your calculations!

Read 539 times

2 Replies

Report

Related Topics

Replies

agelessperson

wrote...

9 years ago

Quote from: Parik (9 years ago)

20.   How many different five-digit numbers can be formed from the set of seven numbers {1,2,3,4,5,6,7} if
a)   Repetition is allowed?
b)   Repetition is not allowed
c)   Repetition is allowed and the third digit must be different from the second digit?
Show your calculations!

Similar Question

How many different five-digit numbers can be formed from the set of seven numbers (1,2,3,4,5,6,7) if repetition is allowed and the third digit must be different from the second digit?

ANS: 7*7*6*7*7

Report

agelessperson

wrote...

9 years ago

Quote from: Parik (9 years ago)

c) Solve for n:
(n+2)!/(n)! = 110

c) (n+2)!/(n)! = 110 (n)!(n+1)(n+2)/(n)! = 110 (n+1)(n+2) = 110 n^2+3n+2 = 110 n^2+3n-108 = 0 (n+12)(n-9) = 0 n = -12, 9

Quote

b) (n=2)! /(n+2)n!

(n+2)!/(n+2)n! = [(n+2)(n+1)!/(n+2)]/n! = (n+1)!/n! = n+1

Quote

23!/20!

10626

Report

New Topic

Home Search Q & A Board Gallery Resource Library Blog Dictionary Chat	Quick Links Start a Topic Latest Topics Unanswered Questions Courses Study Tools Browse by Textbook	Social Facebook YouTube Community Stats Who's Online Trending Staff	Help About Us Take the Tour Study Tips Posting Guidelines Terms and Policies Contact Us
Biology Forums - Study Force © 2010-2024 \| Powered by SMF \| SMF © 2015, Simple Machines \| Sitemap Biology-Forums.com is not affiliated with any publisher. Book covers, title and author names appear for reference only.