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

### Instruction:
A sack of rice, which is 50 kilograms,  costs $50. If David sells it for $1.20 per kilogram, how much will be his profit?

### Response:
 Mapato ya David kwa kilogramu 50 za mchele ni $1.20 x 50 = $<<1.20*50=60>>60.
Hivyo, faida yake ni $60 - $50 = $10.