Xiao Ming rides a bicycle to school, and it takes 40 minutes to walk home; if he walks both ways, it takes 1 hour. If you ride a bicycle back and forth, how much time will it take on the road?
小明上学骑自行车，回家步行路上共需40分钟；若来回都步行，路上就需1小时．若来回都骑自行车，路上需多少时间？
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>