perplexus.info :: Numbers : Easily distinguished codes

Easily distinguished codes (Posted on 2005-11-29)

A certain company gives each of its clients a 10 digit number as a sort of identification code. As a precaution, any pair of used codes should differ by at least two digits so no one accidentally gives someone else's code.

How many clients can they have before adding digits? Give an example of a set of codes they might use. What if each pair of codes must differ by at least 3 digits? 4? More?

See The Solution Submitted by Tristan

Rating: 4.5000 (4 votes)

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
partial answer	K Sengupta	2007-09-24 10:30:11
re(2): 3+ digits?	Tristan	2006-02-26 02:02:53
re: 3+ digits?	goFish	2006-02-25 18:04:31
3+ digits?	Tristan	2006-02-02 19:22:51
Proof?	goFish	2005-12-02 07:42:48
re(2): Spoiler	Leming	2005-12-01 12:34:52
re: Clarification required	Tristan	2005-11-30 19:05:14
Clarification required	goFish	2005-11-30 05:32:24
re: Spoiler	Charlie	2005-11-29 14:11:02
Spoiler	Leming	2005-11-29 12:00:04
Big, big hint	e.g.	2005-11-29 11:02:27

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info