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

### Instruction:
The price of a book was $400. If the book's price is decreased by 15% and then increased by 40%, what is the final price of the book?

### Response:
 Wakati bei ya kitabu inapunguzwa kwa 15%, kupungua kwa jumla ya bei ni 15/100 * $400 = $60
Bei mpya ya kitabu inakuwa $400 - $60 = $340
Baada ya bei ya kitabu kuongezeka kwa 40/100, bei ya kitabu inaongezeka kwa 40/100 * $340 = $136
Bei ya mwisho ya kitabu ni $340 + $136 = $476