Xiao Li's father rides a bicycle when he goes to work, and takes a bicycle when he returns home. The total time spent on the road is 50 minutes. If you cycle all the way back and forth, the total time spent on the road is 70 minutes. If you take a car to and fro, how long will it take you on the way?
小李的爸爸上班时骑车，回家时坐车，路上一共用时50分．如果往返都骑车，路上一共用时70分．如果往返都坐车，路上一共用时几分？
<gadget id="calculator">70 / 2</gadget>
<output>35</output>

<gadget id="calculator">50 - 35</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>