A slow train is 120 meters long and its speed is 15 meters per second; an express train is 160 meters long and its speed is 20 meters per second. The two cars are running towards each other on the double-track track. How many seconds does it take from the front of the train to the rear of the train? bell.
一列慢车车身长120米，车速是每秒15米；一列快车车身长160米，车速是每秒20米，两车在双轨轨道上相向而行，从车头相遇到车尾相离要用多少秒钟．
<gadget id="calculator">120 + 160</gadget>
<output>280</output>

<gadget id="calculator">15 + 20</gadget>
<output>35</output>

<gadget id="calculator">280 / 35</gadget>
<output>8</output>

<result>8</result>