A car drives from place A to place B at a speed of 40 km/h, takes 5 hours, and only takes 4 hours to return. What is the speed of this car when it returns?
一辆汽车从甲地开往乙地，去时的速度为40千米/时，共用5个小时，返回时只用了4个小时，这辆汽车返回时的速度是多少？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">40 * (5/4)</gadget>
<output>50</output>

<result>50</result>