A section of road A takes 20 minutes to complete the journey, and B takes 25 minutes to complete the journey. How much slower is B's speed than A.
一段路甲行完全程要20分钟，乙行完全程要25分钟，乙的速度比甲慢多少．
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 25</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(1/20) - (1/25)</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">(1/100) / (1/20)</gadget>
<output>1/5 = around 0.2</output>

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