Cody was reading through his favorite book series.  The series was 54 books in total.  If Cody read 6 books the first week, and 3 books the second week and then 9 books every week after that.  How many weeks did it take Cody to read his series?
Cody needs to read 54 books - 6 books - 3 books = <<54-6-3=45>>45 books.
Cody read 9 books each week after = 45 books / 9 books per week = <<45/9=5>>5 weeks.
Cody read for 1 week + 1 week + 5 weeks = <<1+1+5=7>>7 weeks total.
#### 7