It takes 20 minutes for A to travel the same distance, and 18 minutes for B. How much slower is A's speed than B's?
行同一段路，甲要20分钟，乙要18分钟，甲的速度比乙的速度慢百分之几？
<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/18) - (1/20)</gadget>
<output>1/180 = around 0.005556</output>

<gadget id="calculator">(1/180) / (1/18)</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>