Questions tagged [calendar-computations]
This tag is for questions about combinatorial and computational issues with regards to calendar systems. A typical, well-known mathematical result in this direction is John Conway's Doomsday Algorithm for computing the "day of the week" associated to a given date.
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Question concerning the solution of a certain calendar problem involving modular arithmetic.
A question I was given is the following:
A certain month on the calendar has 31 days, and it has an equal amount of Mondays and Wednesdays. How many different kind of days(Monday to Sunday) can be ...
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How can I find day of a certain month when the sum of all thursdays is a certain number?.
The problem is as follows:
The sum of all thursdays in certain month is $80$ and equal to the sum
of all sundays in the following month, which has the same number of
mondays than fridays it has ...
- 4,185
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How can I find the name of the last day of a week in certain year when the name of a day of a month for that year is given?
The problem is as follows:
Roger sees in his almanac that a certain month from a year the first
day was monday and the last day was also monday. What day of the week,
was the last day of that ...
- 4,185
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How can I find the a certain birthdate of two people when one information given depends on the other?
The problem is as follows:
Mike was born on $\textrm{October 1st, 2012,}$ and Jack on $\textrm{December 1st, 2013}$. Find the date when the triple the age of Jack is the double of Mike's age.
The ...
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Why the 28 year day-date repetition rule doesn't always follow?
I was studying the pattern of calendar and found out that the years repeat same day-date pattern over a period of 28 years but the pattern broke if we compare 1752 and 1780.(By day-date pattern i mean ...
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What is the maximum number of years I have to wait till my birthday falls again on a Sunday?
Suppose my birthday fell on a Sunday. What is the maximum number of years I may have to wait till my birthday falls on a Sunday again?
My intuition says 11 years:
At the earliest, the next Sunday is ...
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How many times in the future after the 1st of January of 2019 will a palindrome date happen?
I'm trying to solve the following problem:
How many times in the future (before the year 10000) will after the 1st
January of 2019 happen a palindrome date. Date is in the dx-my-ymxd
forum, and ...
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Must each new year always contain a Friday the 13th?
I am wondering if there is any way to determine whether it is possible to have a year that does not contain a Friday the 13th?
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When does adding 180 or 220 years give a date falling on the same day of the week?
Many dates in the Gregorian calendar repeat the day of the week after 180 and/or 220 years. In fact, this was already the case for October 15, 1582 (1582, 1762, and 1802 all had October 15 on a Friday)...
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How many years later the calendar of 2016 can be reused?
How many years later the calendar of 2016 can be reused?
I was asked this question in an exam. I want to explain the term 'reuse' . If we ignore the holidays and our only purpose is to check the date ...
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How to find the week day of (any) given date? [duplicate]
How to find the week day of any given date?
Say we need to know in which week-day was June $25,2019$?
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"New Year falls more often on Sundays than on Mondays"
This is a question from a hungarian math contest from the year 1948.
It was Saturday on the 23rd October, 1948. Can one conclude that New Year falls more often on Sundays than on Mondays?
Well, I ...
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Number of occurrences of a generic recurring event between two dates
Intro
Cron is a very common tool in computer science, which allows to schedule an event given a generic pattern written in a file called crontab. I'm researching on an algorithm to calculate the ...
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Why don't we subtract out / ignore the leap year every 128 years? [closed]
When we add the extra day to the calendar every 4 years it's to "correct" the calendar under the assumption that the year's length is 365.25 days. Every year, you're .25 days off, so after 4 years, ...
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I want to know what not integer numbers means in calendar?
I want to know what not integer numbers means in this case?
if $30$ days $= 4$ weeks and $2$ days $4.2$
then why $20$ days does not correspond to $2$ weeks and $8$days $4,8$?
being that: $\frac{30}{...
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