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 Prime Time (Posted on 2002-12-17)
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.

 Subject Author Date Thoughts On A Possible Extension K Sengupta 2008-02-26 23:36:54 Puzzle Solution K Sengupta 2008-02-26 22:31:03 re(3): German solution Hugo 2005-12-30 02:40:22 re(2): German solution MindRod 2005-12-29 21:55:16 re: German solution Hugo 2005-12-29 03:32:38 German solution MindRod 2005-12-29 00:00:29 easy ethan 2003-05-08 10:51:19 re(2): simple guess Gamer 2003-04-26 12:16:42 re: simple guess TomM 2002-12-17 03:31:00 simple guess Nick Murray 2002-12-17 02:57:24

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