Teacher Wang took a car to work and walked home. It took a total of 60 minutes on the road, and it only took 40 minutes to take a car to and fro. How many minutes will it take to walk both ways.
王老师上班时坐车，回家时步行，在路上一共花了60分钟，往返都坐车，只需40分钟．如果往返都步行，需要多少分钟．
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<result>80</result>