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

### Instruction:
 约翰购买了20块肥皂，每块重1.5磅，每磅价格为0.5美元。他在肥皂上花了多少钱？


### Response:
 他购买了20*1.5=<<20*1.5=30>>30磅的肥皂
那花费了30*.5=$<<30*.5=15>>15。