A car travels from point A to point B. It takes 5 hours to go and 4 hours to return. How much faster is the speed when returning than when going.
一辆汽车从A地到B地，去时用了5小时，回时用了4小时，回时的速度比去时的速度快多少．
<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>