Xiao Ming walks from A to B. He walked the whole distance (1/4) in the first hour, and 30% of the whole distance in the second hour. At this time, the distance traveled has exceeded the midpoint of the two places by 2 kilometers. How many kilometers are there between A and B?
小明从甲地步行去乙地，第一小时行了全程的(1/4)，第二小时行了全程的30%，这时已行路程超过了两地中点2千米．甲、乙两地相距多少千米？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/10) - (1/2)</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">2 / (1/20)</gadget>
<output>40</output>

<result>40</result>