How many weeks is 3 months?
Let us solve it with simple math.
1 year = 12 months
1 month = 30/31 days (barring February as it has 28 days)
7 days make up a week
1 month = (28/7=)4 weeks and 2 or 3 days
So, the following are the possibility of
Total number of weeks per 3 months
3 months = (4+4+4) weeks + [(2+3+3) or (3+2+3) or (3+3+2)] days = 12 weeks + 8 days = 13 weeks + 1 day
3 months = (4+4+4) weeks + (2+3+2) days = 12 weeks + 7 days = 13 weeks
3 months = (4+4+4) weeks + [(3+0+3) or (0+3+2)] days = 12 weeks + (6 or 5) days [For February]