It takes 5 hours for a car to go from city A to city B. Now it takes 4 hours after increasing the speed. How much is the speed increased now than before?
一辆汽车从甲城到乙城需要5小时，现在提高速度后需要4小时，现在行驶的速度比原来提高了多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">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) / (1/5)</gadget>
<output>1/4 = around 0.25</output>

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