5. In a certain month, there are more Mondays than Tuesdays, and more Sundays than Saturdays. What day of the week is the 5th of this month? Could this month be December?
5. From the 1st to the 28th, these four weeks have four Mondays, four Tuesdays, ... four Sundays. From the given conditions, we know that the 29th is a Tuesday, the 30th is a Wednesday, and this month does not have a 31st. Therefore, the 1st of this month is a Sunday, and the 5th is a Thursday.
This month cannot be December.