person rides a bicycle from the county seat to the township to set up a factory. He starts from the county seat by bicycle and completes half of the journey in 30 minutes. At this time, he speeded up and traveled 50 meters more per minute than before. After riding for another 20 minutes, he knew from the mileage sign on the side of the road that he had to ride another 2 kilometers to reach the township factory. So what is the total distance between the county seat and the township to set up a factory?
一个人从县城骑车去乡办厂，他从县城骑车出发，用30分钟行完了一半路程．这时，他加快了速度，每分钟比原来多行50米，又骑了20分钟后，他从路旁的里程标志牌上知道，必须再骑2千米才能赶到乡办厂．那么县城到乡办厂之间的总路程是多少．
<gadget id="calculator">20 / 1_000</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">50 * (1/50)</gadget>
<output>1</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">20 / 1_000 / 2</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">50 * (1/100)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / 30</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (1/2)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">3 / (1/6)</gadget>
<output>18</output>

<result>18</result>