Mom takes a car to work and walks to and from get off work. It takes 90 minutes on the road. If she walks both ways, it will take 140 minutes. How many minutes will it take if she takes a car both ways?
妈妈上班坐车，下班走路，在路上共用90分钟，如果往返都走路，要140分钟，如果往返都坐车要多少分钟？
<gadget id="calculator">140 / 2</gadget>
<output>70</output>

<gadget id="calculator">90 - 70</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>