All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
50 - Digit Number (Posted on 2003-11-15) Difficulty: 3 of 5
A number of 50 digits has all its digits equal to 1 except the 26th digit. If the number is divisible by 13, then find the digit in the 26th place.

See The Solution Submitted by Ravi Raja    
Rating: 3.3333 (6 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Less thinking using extended precision | Comment 3 of 39 |
(In reply to solution by Charlie)

The mod-13 values could be found directly via extended precision provided by UBASIC:


list
10 point 15
20 for I=0 to 49
30 N=N+10^I
40 next
50 print N@13
60 print (10^24)@13
OK
run
11
1
OK

telling us the original mod value and the mod value
for each additional point in the 26th position, then:

? 11111111111111111111111113111111111111111111111111 @ 13
0
OK

---------
With the latter immediate-mode print command (the ?) being a check on the answer.

  Posted by Charlie on 2003-11-15 11:46:40
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 (10)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information