It took Xiao Ming 20 minutes to go from home to school, and 16 minutes to return home from school along the original road. How much faster is the return speed than when he went?
小明从家到学校用了20分钟，从学校沿原路返回家用了16分钟，返的速度比去时提高了多少
<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

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

<gadget id="calculator">(1/16) - (1/20)</gadget>
<output>1/80 = around 0.0125</output>

<gadget id="calculator">(1/80) / (1/20)</gadget>
<output>1/4 = around 0.25</output>

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