If a train with a length of 0.1 kilometers passes through a tunnel with a length of 0.4 kilometers at a speed of 50 kilometers per hour, how many minutes will it take?
长度为0.1千米的列车，如果以每小时50千米的速度通过一个0.4千米长的隧道，要用多少分钟．
<gadget id="calculator">0.1 + 0.4</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 / 50</gadget>
<output>0.01</output>

<gadget id="calculator">0.01 * 60</gadget>
<output>0.6</output>

<result>0.6</result>