Xiao Ming walks along the road, every 12 minutes there is a bus passing him from behind, every 4 minutes there is a bus coming from the front, if the speed of Xiao Ming and the car is always the same, how many times Minutes from the starting point a bus.
小明沿着马路往前走，每隔12分钟就有一辆公共汽车从后面超过他，每隔4分钟就有一辆公共汽车由前面开过来，如果小明和汽车的速度始终不变，那么每隔多少分钟从起点发出一辆公共汽车．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) + (1/12)</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>