It is known that the distance traveled by a truck in 2 hours is equivalent to 40% of the distance traveled by a passenger car in 4 hours. How much slower is the speed of a truck than a passenger car?
已知一列货车2小时所行的路程相当于一列客车4小时所行路程的40%，货车的速度比客车慢多少
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) / 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 * (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) / (1/4)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>