A train of passenger cars is 190 meters long, and a train of freight cars is 240 meters long. The two trains are moving towards each other at speeds of 20 meters and 23 meters per second respectively. On a double-track railway, how long does it take for two cars to meet at the front and leave at the rear?
一列客车长190米，一列货车长240米，两列分别以每秒20米和23米的速度相向行进．在双轨铁路上，两车从车头相遇到车尾离开一共需要多少时间？
<gadget id="calculator">190 + 240</gadget>
<output>430</output>

<gadget id="calculator">23 + 20</gadget>
<output>43</output>

<gadget id="calculator">430 / 43</gadget>
<output>10</output>

<result>10</result>