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

### Instruction:
 Tracy, Michelle, and Kati一起去了一次总里程为1000英里的公路旅行。Tracy开车比Michelle多开了20英里，而Michelle开车的里程是Kati的3倍。Michelle开了多少英里？


### Response:
 让x代表Kati开车的英里数
Michelle:3x
Tracy:20+2(3x)=20+6x
总里程:x+3x+20+6x=1000
10x+20=1000
10x=980
x=<<98=98>>98英里
3(98)=<<3*98=294>>294英里