The station sends out trains at the same time. A person riding a bicycle finds that a car drives past every 12 minutes, and a car drives past every 4 minutes. How many minutes does the station send a car?
车站每隔相同的时间发一次车，有一个人骑着自行车，发现背后每隔12分钟开过来一辆汽车，而迎面每隔4分钟有一辆汽车驶过去．车站每隔多少分钟发一辆车？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

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

<gadget id="calculator">(1/12) + (1/4)</gadget>
<output>1/3 = around 0.333333</output>

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

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

<result>6</result>