Xiaoming goes from A to B, starts to ride a bicycle for (1/3) distance, and rides for (2/3) distance; when returning from B to A, rides for (3/5) distance, (2/ 5) Take a car for the distance, but it takes half an hour longer to come back than to go. It is known that Xiao Ming travels 12 kilometers per hour by bicycle, and 30 kilometers per hour by car. How many kilometers are there between A and B?
小明从甲地去乙地，开始(1/3)的路程骑车，(2/3)的路程乘车；从乙地返回甲地时，(3/5)的路程骑车，(2/5)的路程乘车，结果回来时比去时多用半小时．已知小明骑车每小时行12千米，乘车每小时30千米．甲乙两地相距多少千米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(3/5) * (1/12)</gadget>
<output>1/20 = around 0.05</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">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) * (1/12)</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (1/30)</gadget>
<output>1/45 = around 0.022222</output>

<gadget id="calculator">(1/75) - (1/36) - (1/45)</gadget>
<output>-11/300 = around -0.036667</output>

<gadget id="calculator">(1/20) + (-11/300)</gadget>
<output>1/75 = around 0.013333</output>

<gadget id="calculator">(1/2) / (1/75)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>