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Prime Time (Posted on 2002-12-17) Difficulty: 2 of 5
There are 362,880 different numbers that use the digits 1 to 9 exactly once (like 187,432,569).

Of these, what percentage are prime numbers?

  Submitted by cges    
Rating: 3.1538 (13 votes)
Solution: (Hide)
An old problem

Please see the solutions in the comments.
My solution below is short and sweet, but some of the others given are well thought out and appreciated.

The answer is - 0%. All those numbers add up to 45 or 5 * 9. All are divisible by 9.

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Some ThoughtsThoughts On A Possible ExtensionK Sengupta2008-02-26 23:36:54
SolutionPuzzle SolutionK Sengupta2008-02-26 22:31:03
re(3): German solutionHugo2005-12-30 02:40:22
re(2): German solutionMindRod2005-12-29 21:55:16
re: German solutionHugo2005-12-29 03:32:38
SolutionGerman solutionMindRod2005-12-29 00:00:29
Solutioneasyethan2003-05-08 10:51:19
re(2): simple guessGamer2003-04-26 12:16:42
re: simple guessTomM2002-12-17 03:31:00
simple guessNick Murray2002-12-17 02:57:24
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