The distance between two cities is 300 kilometers, and the speed of a passenger train is 100 kilometers per hour when it goes out and 60 kilometers per hour when it comes back.
两个城市之间的路程为300千米，一列客车去时的速度为每小时100千米，回来时的速度为每小时60千米，那么该列客车来回一次的平均速度为多少千米．
<gadget id="calculator">300 / 100</gadget>
<output>3</output>

<gadget id="calculator">300 / 60</gadget>
<output>5</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">300 * (1/4)</gadget>
<output>75</output>

<result>75</result>