perplexus.info :: Just Math : Prime Time Revisited

Prime Time Revisited (Posted on 2004-10-22)

Do there exist three 2-digit primes such that:

Any two of the three, averaged, produce another prime, and
The average of all three is prime

Submitted by SilverKnight

Rating: 3.0000 (8 votes)

Solution: (Hide)

Yes: 11, 47, and 71
(11 + 47) / 2 = 29
(11 + 71) / 2 = 41
(47 + 71) / 2 = 59
(11 + 47 + 71) / 3 = 43

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

Subject	Author	Date
Methodology and result	K Sengupta	2005-11-08 00:29:08
Submission Query	K Sengupta	2005-11-08 00:17:58
Solution to "Prime Time Revisited"	K Sengupta	2005-08-29 08:03:55
re(4): Arithmetic progression	Tristan	2004-10-25 03:41:52
re(3): Arithmetic progression	owl	2004-10-24 17:16:23
re(2): Arithmetic progression	owl	2004-10-24 16:17:06
re: Arithmetic progression	owl	2004-10-24 16:10:34
Arithmetic progression	Brian Smith	2004-10-22 22:23:00
Brute Force Solution	np_rt	2004-10-22 16:53:07
UBASIC program	Charlie	2004-10-22 15:40:33
re: Answer + Solution (semi brute force)	RandyOrton	2004-10-22 15:23:33
re(2): Spoiler.	Juggler	2004-10-22 14:42:07
re: Spoiler.	nikki	2004-10-22 14:30:59
Answer + Solution (semi brute force)	nikki	2004-10-22 14:29:34
Sieve of Eratosthenes (solution)	Penny	2004-10-22 14:27:23
First part : Not so uncommon	Syzygy	2004-10-22 13:42:00
Spoiler.	Juggler	2004-10-22 13:24:22

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