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ANSWER: 28 different plates. He’d need seven plates for 31-day months (with the first day of the month on different weekdays), another seven plates for 30-day months, and another seven plates for February’s 28 days. He’d also need an additional seven plates for leap year Februarys, which have 29 days.
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is it 28? 7 for the months with 31 days, 7 for those with 30, 7 for february and another 7 for a leap year. that way you have a plate for when the 1st lands on any day of the week.
posted by grant on 8-19-2008 at 7:31 am
I have an even tougher question. This came up while I was arguing about what days we would get off from our jobs for Thanksgiving. One of my coworkers said that his birthday is on Thanksgiving every four years. This sounded a little bit fishty so I went through the process of figuring out just what days could possibly have Thanksgiving happen on them. I found that he just had run into a bit of luck lately with leap years (and the non-leap year of 2000). So here’s my question: What days in November can Thanksgiving occur upon? For and even trickier task, what is my co-workers birthday?
posted by Gary on 8-19-2008 at 8:19 am
This seems wrong though. Since George would be using plates, would it not be simpler to just create the 7 plates for 31 days and then add the ink appropriately for days with 30/29/28 days so in the end he only really needs 7 plates and a knowledgeable use of ink.
Or am I thinking to hard?
posted by Aram Dermenjian on 8-19-2008 at 8:58 am
Gary: In the US, Thanksgiving is celebrated on the fourth Thursday of November, so the possible dates are Nov 22-28.
Was your friend’s birthday on the 23rd?
posted by TomH on 8-19-2008 at 9:01 am
Good thought, Aram, and I considered that notion — that he could “block” unused dates for months with fewer than 31 days. That’s why I phrased his thought to say that he’d simply add the month & year and “be done.” If he had to mess with the ink on certain months, it would require additional work for several months each year.
In the same vein, though, if he offered yearly calendars instead of monthly ones, he’d only need 14 plates (7 regular, 7 leap year) instead of 28.
posted by Sandy on 8-19-2008 at 9:06 am
Gary — 2000 was a leap year. Leap years occur every 4 years except years ending in “00″ not divisible by 400. So 1700, 1800, and 1900 were not leap years, but 1600 and 2000 were.
Bit of trivia: 1900 was the only non-leap-year in which the modern Olympics were held
posted by Kevin H on 8-19-2008 at 1:11 pm
My nephew was born on 11/27/03, which was Thanksgiving. (And yes, we called him “Butterball.”) His next birthday, the big 0-5, is on Thanksgiving again. So, it does repeat, although not exactly every four years.
posted by Cassie on 8-19-2008 at 4:30 pm