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

### Instruction:
 Alexa na Emily wamefungua biashara ya limau mbele ya nyumba. Walitumia $10 kununua limau, $5 kununua sukari na $3 kununua vikombe. Limau moja ni $4. Waliuza jumla ya vikombe 21. Waliweza kupata faida kiasi gani baada ya kulipa gharama?


### Response:
 Walitumia $10 + $5 + $3 = $<<10+5+3=18>>18.
Walipata $4 x 21 = $<<4*21=84>>84.
Walipata faida ya $84 - $18 = $<<84-18=66>>66.