It took 5 hours for the car to travel from A to B, and 4 hours to return from B to A. How much faster is the speed when returning than when going.
汽车从A地到B地用了5小时，从B地返回A地用了4小时．返回时速度比去时快了多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) / (1/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>