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

### Instruction:
Stanley sold 4 cups of lemonade an hour. His brother, Carl, sold 7 cups of lemonade an hour. How many more cups did Carl sell than Stanley in 3 hours?

### Response:
 Stanley aliuza vikombe 4 x 3 = <<4*3=12>>12
Carl aliuza vikombe 7 x 3 = <<7*3=21>>21
Carl aliouza vikombe 21 - 12 = <<21-12=9>>9 zaidi ya Stanley.