My birthday is on the thirteenth of August 1987. How often does it fall on Friday the thirteenth and when will the next occurence be?
2007-07-13 06:33:52 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
If it weren't for leap years, we could say it happens every 7 years. However, because of the leap years, it can happen anywhere from every 5th year to every 12th year.
For example
8/13 was a Friday in 1982, but then not again until 1993. Then it fell on Friday in 1999, 2004 and will happen again in 2010.
Incidentally, there is a function on Excel you can use to calculate which day of the week any date was. It's called "WEEKDAY". (That's how I figured out how to answer your question.)
2007-07-13 06:44:44 · answer #1 · answered by Mathematica 7 · 1⤊ 0⤋
On Friday October 13, 1307 Philip ordered de Molay and scores of other French Templars to be simultaneously arrested. The Templars were charged with numerous heresies and tortured to extract false confessions of blasphemy. The confessions, despite having been obtained under duress, caused a scandal in Paris. After more bullying from Philip, Pope Clement then issued the bull Pastoralis Praeeminentiae on November 22, 1307, which instructed all Christian monarchs in Europe to arrest all Templars and seize their assets. They were pretty much killed and stuff after that too so that's why.
2016-04-01 02:36:50 · answer #2 · answered by ? 4 · 0⤊ 0⤋
It happens every six years unless leap year causes it to skip Friday.
I had my last b-day on Fri the 13th and the 6 years ago was Fri. the 13th but I won't have it again in six years because leap year will make it skip over a Friday. So now my next Friday the 13th b-day will be in 2018 (I think, if I did the math right).
2007-07-13 06:45:26 · answer #3 · answered by Lady Geologist 7 · 1⤊ 0⤋
Calendars repeat themselves every 28 years (4 times 7, for leap years). So it will definitely repeat every 28 years. (EXCEPT AT A 1,000 YEAR BOUNDARY THAT IS not DIVISIBLE BY 4, OR at some 400 year boundaries. For our lifetimes it will be every 28 years.) That is an interesting problem to work out...
Ron.
2007-07-13 06:45:59 · answer #4 · answered by Anonymous · 1⤊ 0⤋
The next 3 are in 2010,2021 & 2027
2007-07-13 08:37:58 · answer #5 · answered by Ollie 7 · 1⤊ 0⤋
each year the day of your birthday gets moved up one week day...so your b'day will be on a friday every 7 years (provided it's a regular year)
2007-07-13 06:41:26 · answer #6 · answered by GD-Fan 6 · 1⤊ 0⤋
depending on leap year and all that, but most likely once or twice every 7 years!
#
2007-07-13 06:42:29 · answer #7 · answered by Klick 5 · 1⤊ 0⤋
2010
2021
2027
2032
It would be every 7 years, but leap year messes it up.
2007-07-13 08:17:50 · answer #8 · answered by Baysoc23 5 · 1⤊ 0⤋
Indeterminate.
2007-07-13 07:18:01 · answer #9 · answered by ag_iitkgp 7 · 0⤊ 3⤋
Ask the Internet.
2007-07-13 06:49:14 · answer #10 · answered by Anonymous · 0⤊ 2⤋