What Is the Probability of Having 5 Sundays in a 31-Day Month?
Learn the probability of five Sundays occurring in a 31-day month and understand the calendar configurations that make it possible.
Video transcript
The probability of having 5 Sundays in a month of 31 days is approximately 45.2%. In a 31-day month, there are always 4 weeks plus 3 extra days. Those extra days must include a Sunday, making certain configurations possible.
Questions and answers
How many Sundays are usually in a 31-day month?
Typically, a 31-day month contains either 4 or 5 Sundays, depending on which day of the week the month starts.
What determines if a month has 5 Sundays?
If the month starts on a Sunday or earlier in the week such that the extra days after 4 full weeks include a Sunday, the month will have 5 Sundays.
Is the probability of 5 Sundays the same for months with 30 days?
No, months with 30 days have a lower chance of having 5 Sundays because they have fewer extra days beyond the 4 full weeks.
Related questions
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For more insights into calendar probabilities and date-related questions, explore our related videos on weeks per month, leap year effects, and calculating day distributions in months.
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