4 weeks and 2 days.
There are about 134½ weeks between 1 January 2011 and 31 July 2013.
41 weeks and 3 days.
34 weeks and 6 days.
1/9 to 1/31 is three weeks. Since there are 52 weeks in a year, 1/31 to the following 1/9 is 49 weeks.
8.6 weeks
39 weeks
Weeks there were between January 1 2009 to December 31 2009 is 52.
31
Between January 1 and October 31 there are 39 weeks.
34 weeks and 6 days.
31 days. Always 31 days.
That's about 30 weeks.