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

### Instruction:
The total number of books on four shelves, with 400 books each, is the same as the distance in miles that Karen bikes back to her home from the library. Calculate the total distance that Karen covers if she bikes from her home to the library and back.

### Response:
 Idadi jumla ya vitabu kwenye rafu nne ni 400*4 = <<400*4=1600>>1600 vitabu.
Kwa kuwa idadi jumla ya vitabu kwenye rafu ni sawa na umbali ambao Karen anapanda kurudi nyumbani, kupanda baiskeli kwenda na kurudi maktaba kunachukua 1600+1600 = 3200 maili.