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

### Instruction:
 约翰·史密斯买了3个蛋糕，每个蛋糕12美元，然后与他的兄弟平分了费用。他支付了多少钱？


### Response:
 这些蛋糕的总价是3*12 = 36美元。
所以他支付了36美元/2 = 18美元。