Question 1183662
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If there are 40 students and only 12 months in which any of them could have been born, then the average number of birthdays per month is three and one-third.  Since you cannot have a third of a birthday, it will be better to consider integer division of 40 by 12, namely a quotient of 3 and a remainder of 4.  Those four must have been born in a month or months that already have 3 birthdays, so yes, at least one month has 4 birthdays.  In fact, if 4 is the most birthdays in any given month, then there are 4 months that have 4 birthdays each.


																
John
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My calculator said it, I believe it, that settles it
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