person walks at a speed of 10 kilometers per hour and rides a bicycle at a speed of 30 kilometers per hour. He walks (2/5) the distance from A to B and rides (3/5) the distance. Then return to Jiadi along the original road, walk in (3/5) time, and cycle in (2/5) time when returning, and the result is 30 minutes slower than when going. What is the distance between A and B?
某人步行速度是每小时10千米，骑自行车的速度是每小时30千米，他从甲地回到乙地(2/5)的路程走路，(3/5)的路程骑车．然后沿原路返回甲地，返回时(3/5)的时间走路，(2/5)的时间骑车，结果比去时慢了30分钟．则甲、乙两地的路程是多少．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(3/5) * (1/10)</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(2/5) * (1/30)</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">(2/5) * (1/10)</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">(3/5) * (1/30)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/75) - (1/25) - (1/50)</gadget>
<output>-7/150 = around -0.046667</output>

<gadget id="calculator">(3/50) + (-7/150)</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">0.5 / (1/75)</gadget>
<output>37.5</output>

<result>37.5</result>