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

### Instruction:
 Stanley a vendu 4 tasses de limonade par heure. Son frère, Carl, a vendu 7 tasses de limonade par heure. Combien de tasses Carl a-t-il vendu de plus que Stanley en 3 heures ?


### Response:
 Stanley a vendu 4 x 3 = <<4*3=12>>12 tasses.
Carl a vendu 7 x 3 = <<7*3=21>>21 tasses.
Carl a vendu 21 - 12 = <<21-12=9>>9 tasses de plus que Stanley.