Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
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?

### Response:
 Cody anahitaji kusoma vitabu 54 - 6 vitabu - 3 vitabu = <<54-6-3=45>>45 vitabu.
Cody alisoma vitabu 9 kila wiki baada ya hapo = 45 vitabu / 9 vitabu kwa wiki = <<45/9=5>>5 wiki.
Ilimchukua Cody wiki 1 + wiki 1 + wiki 5 = <<1+1+5=7>>7 wiki jumla kusoma safu yake.