ALL months have 28 days! Should have said "Why does February have 28 days and some have 31?".
February
The riddle answer is "12." -- all 12 of them have at least 28 days.Only February, in years that are not leap years, has exactly 28 days.Of the others, 4 have 30 days and 7 have 31 days.(see related question)
Depends on which 3 months you mean, some months have 30 days and some have 31, February has 28. So about 90.
11 months have 29 days..........Only feb has 29 days in the leap year otherwise it has 28 days.
All 12 months have "at least" 28 days. Only February has exactly 28 days, except in leap year.
The average days in 9 months is 274 days. The exact answer to this question depends on the months in question, because some of the months may have 30 or 31 days or 28, or 29 days.
5 months don't have 31 days, 7 months do. February has 28, or 29 in leap years. April, June, September, and November have 30 days.
all 12 have 28 days...
A month can be an interval of 28, 29, 30, or 31 days. (Look at a calendar.) 640 days = 20.6452 months of 31 days. (rounded) 21.3333 months of 30 days. (rounded) 22.0690 months of 29 days. (rounded) 22.8571 months of 28 days. (rounded)
29, 30 or 31 depending on the month30 days in some months, 31 days in others. In February, there are 28 days (except leap years, where there are 29).
29, 30 or 31 depending on the month30 days in some months, 31 days in others. In February, there are 28 days (except leap years, where there are 29).
Count your knuckles. the hump are the months with 31 days, and the spaces are the months that have less than 31 days. February is the only month that has 28 or 29 days.