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

### Instruction:
 一条裤子需要8.5英尺的布料。阮需要为婚礼做7条裤子。他有3.5码的布料。阮还需要多少英尺的布料来做裤子？


### Response:
 裤子 = 8.5 * 7 = <<8.5*7=59.5>>59.5英尺
3.5码 = 10.5英尺
59.5 - 10.5 = <<59.5-10.5=49>>49
阮还需要49英尺的布料。