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Prime Birthdays (Posted on 2005-03-23) Difficulty: 3 of 5
Assuming a lifespan of 80 years, in what years of the 20th and 21st centuries (1900-1999), (2000-2099) would you have to be born to have the maximum number of prime birthdays in a prime year?

In what years of the same time spans would you have to be born to have the minimum number of prime birthdays in a prime year?

You may assume that people born on Feb. 29 in a leap year still celebrate their birthdays each following year.

See The Solution Submitted by Erik O.    
Rating: 3.0000 (2 votes)

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Puzzle Answer Comment 2 of 2 |
A person have to be born in 2070 to have the maximum number(12) of prime birthdays in a prime year.
The detais are:
2070    born
2081    11
2083    13
2087    17
2089    19
2099    29
2111    41
2113    43
2129    59
2131    61
2137    67
2141    71
2143    73

The minimum is zero, as anyone born in an odd year that's not two years before a prime year will always have his prime ages in even years, except for the second birthday, which in the cases considered is not prime.


Edited on October 28, 2023, 10:48 am
  Posted by K Sengupta on 2023-10-28 10:46:03

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