How many seconds does it take for a 150-meter-long train to travel through a 300-meter-long tunnel at a speed of 18 meters per second?
长150米的火车以18米/秒的速度穿越一条300米长的隧道，穿越要多少秒．
<gadget id="calculator">150 + 300</gadget>
<output>450</output>

<gadget id="calculator">450 / 18</gadget>
<output>25</output>

<result>25</result>