Every 823 years there are 5 weekends in July!
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Oh, come on! Get the blood flowing! In 2011, there are 53 Saturdays. January 1 was a Saturday, and the 53rd Saturday is December 31. So there are, as would be typical, 52 full week-ends all in 2011. (This is not that silly question about 5 of a given week day in a month.) Take the 52 full week-ends in 2011 and take any five of them in a row. I count about 48 possibilities during 2011, including overlaps, of course. And this is only one way to reckon "5 week-ends". Any five week-ends out of the 52 would do, giving an unimaginably large number of possibilities. Something close to 52!/47!. Of course, the questioner may have forgotten to put something in related to the month question.
1955 was a common year starting on a Saturday. As of 2011, the next time this year will happen is in 2022.
Nothing. Their calendar simply ended around this year.
Any month with 30 or 31 days can have 5 weekends (Sat-Sun) if it starts on a Saturday - for 30 day months - or a Friday or Saturday - for 31 day months. Months with only 4 weekends are any February, or any month that does not start on a Friday or Saturday. A non-leap year calendar year will have either 52 or 53 weekends, and will have either 2 or 3 months with 5-day weekends.
That will happen in the year 2030.
Not often, as the calendar changes every year
you would get the time of year wrong
No, there was no Canadian GP in the year 2009. The event did not happen because Canada was not part of the F1 racing calendar in the year 2009. However it was back in the calendar in the year 2010.
1954 was a common year starting on Friday. As of 2012, the next time such a year will happen is in 2021.
April is not a month in the Hebrew calendar, and the Sundays in any Hebrew month could easily change from year to year, just as they often do for any month in the civil calendar.
The quick and dirty answer: Because the number of days in a year is not an exact whole number. So the moment when one full orbit is completed will not always happen at midnight of the same calendar day. In fact, it can happen at any time of night or day. The calendar has to be adjusted now and then so that the seasonal drift doesn't get too big.
No, not at all. People often do it, to check up a date for the following year. There is nothing unlucky about doing it.
The term "synchronize" is unclear. The Islamic Calendar has a year of only 354 days, so it can never be the same length as a solar year (usually calculated with the Gregorian Calendar with an average of years length of 365.24 days). However, the date on the Islamic Calendar and on the Gregorian Calendar will correlate every 34 Islamic Calendar Years which correspond to 33 Gregorian Calendar Years.