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)
28 months = 852.2 days.
They all do because its saying how many months have 28 days not what months only have 28 days
As a riddle answer, you might say "All of them have 25" along with 3 to 6 more days. However, in the commonly used calendar (the Gregorian Calendar), no month has exactly 25 days. The months may have 28, 29, 30, or 31 days.
All 12 months have "at least" 28 days. Only February has exactly 28 days, except in leap year.
The riddle answer is "12" because all 12 months contain "at least" 28 days. February is the only month that has 28 days exactly, but 29 in a leap year.(The trick is that everyone says "1" because of this distinction. The version "If there are 7 months that have 31 days and 11 months that have 30 days, how many months have 28 days?" telegraphs the answer unless someone doesn't know how many months there are in total. So it is either erroneous or trivial.)
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)
28 months = 852.2 days.
11. The question is not specifically asking how many months have "exactly" 30 days. 11 months have "at least" 30 days. There are four months that do have exactly 30 days, and there are at least five different versions of this riddle.
They all do because its saying how many months have 28 days not what months only have 28 days
All 12 months have "at least" 28 days. Only February has exactly 28 days, except in leap year.
All twelve months have at least 28 days, February has exactly 28 days except for leap years.
As a riddle answer, you might say "All of them have 25" along with 3 to 6 more days. However, in the commonly used calendar (the Gregorian Calendar), no month has exactly 25 days. The months may have 28, 29, 30, or 31 days.
852.23 days
Technically all 12 months have at least 28 days in them. However, I suspect you are actually asking how many months have only 28 days. In that case, February is the only month to have only 28 days in its month (except for leap year when it has 29 days).
February has 28 days
One. All the rest have at least 28 days.