It takes 55 seconds for a train to pass through the 800-meter-long bridge (from the front of the train to the bridge to the rear of the train), and it takes 40 seconds to pass through the 500-meter tunnel (from the front of the train to the tunnel to the rear of the train to leave the tunnel). How many seconds does it take for this train to pass another train with a length of 384 meters and a speed of 18 meters per second?
一列火车通过800米长的大桥要55秒(从车头上桥到车尾离桥)，通过500米的隧道要40秒钟(从车头进隧道到车尾离开隧道)．问该列车与另一列长384米、每秒钟行18米的列车迎面错车而过需要多少秒钟？
<gadget id="calculator">800 - 500</gadget>
<output>300</output>

<gadget id="calculator">55 - 40</gadget>
<output>15</output>

<gadget id="calculator">300 / 15</gadget>
<output>20</output>

<gadget id="calculator">20 * 40</gadget>
<output>800</output>

<gadget id="calculator">300 + 384</gadget>
<output>684</output>

<gadget id="calculator">20 + 18</gadget>
<output>38</output>

<gadget id="calculator">684 / 38</gadget>
<output>18</output>

<result>18</result>