On a road, Xiao Ming rides a bicycle and goes in the same direction as Xiao Guang. The speed of Xiao Ming’s bicycle is three times that of Xiao Guang. Every 10 minutes, a bus passes Xiao Guang, and every 20 minutes, a bus passes him. Xiao Ming, if a bus departs from the departure station at the same interval each time, how many minutes is the interval between two adjacent buses?
在一条马路上，小明骑车与小光同向而行，小明骑车速度是小光速度的3倍，每隔10分钟有一辆公共汽车超过小光，每隔20分由一辆公共汽车超过小明，如果公共汽车从始发站每次间隔同样的时间发一辆车，那么相邻两车间隔多少分钟？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/10) - (1/20)</gadget>
<output>1/20 = around 0.05</output>

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

<gadget id="calculator">(1/20) / 2</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(1/40) + (1/10)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / (1/8)</gadget>
<output>8</output>

<result>8</result>