50 - Digit Number II (Posted on 2005-05-13)

	Submitted by Dustin
Rating: 2.8000 (5 votes)
Solution:	(Hide)
0. Any number made up of entirely 1's is divisible by 239 if the number of 1's is divisible by 7. So you could have a 49-digit number divisible by 239 in which every digit would be 1. If you multipliled by 10, you would get a 0 at the end, so 0 is the digit that is different.

	Subject	Author	Date
	Puzzle Thoughts	K Sengupta	2022-01-31 21:26:02
	Assuming leading zeroes	K Sengupta	2008-05-18 02:25:02
	Proof of f(7n) being divisible by 239	K Sengupta	2008-05-18 02:24:00
	Puzzle Solution	K Sengupta	2008-05-18 02:22:15
	Answer	K Sengupta	2008-05-15 16:19:29
	re(2): A systematic approach	phi	2005-06-22 08:17:53
	Solution, but not very generic	Bruno	2005-05-17 02:22:28
	re: A systematic approach	Justin	2005-05-13 21:18:35
	A systematic approach	Charlie	2005-05-13 18:00:09
	re: Solution by lucky guess	Erik O.	2005-05-13 17:12:33
	the best I achieved, until now. I'm still trying...	pcbouhid	2005-05-13 17:10:30
	Solution by lucky guess	Jer	2005-05-13 16:55:53