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

### Instruction:
Jack bought 3 books a month at $20 each.  He sells them back at the end of the year for $500.  How much money did he lose?

### Response:
 Alinunua vitabu 3*20=$<<3*20=60>>60 kwa mwezi.
Hii inamaanisha alinunua vitabu 60*12=$<<60*12=720>>720 kwa mwaka.
Hivyo, alipoteza 720-500=$<<720-500=220>>220.