A car travels from city A to city B for 5 hours at a speed of 30 km/h. When it returns, it only takes 3 hours. What is the speed of the car when it returns?
一辆汽车从甲城开到乙城，用了5小时，速度为30千米/时，返回时，只用了3小时，汽车返回时的速度是多少？
<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">30 * (5/3)</gadget>
<output>50</output>

<result>50</result>