It took Xiaohong 20 minutes to go from home to school, and 8 minutes to return home from school along the original road. How much has the speed increased?
小红从家到学校，用了20分钟，从学校沿原路返回家用了8分钟，速度提高了多少．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

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

<gadget id="calculator">(1/8) - (1/20)</gadget>
<output>3/40 = around 0.075</output>

<gadget id="calculator">(3/40) / (1/20)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>