There are two trains. Car A is 150 meters long and travels 25 meters per second. Car B is shorter (1/3) than train A and travels 20 meters per second. Now the two trains are moving towards each other. How many seconds?
有两列火车，甲车长150米，每秒行25米，乙车的长度比甲车短(1/3)，每秒行20米，现在两车相向而行，从相遇到相离需几秒钟？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">150 * (2/3)</gadget>
<output>100</output>

<gadget id="calculator">150 + 100</gadget>
<output>250</output>

<gadget id="calculator">25 + 20</gadget>
<output>45</output>

<gadget id="calculator">250 / 45</gadget>
<output>50/9 = around 5.555556</output>

<result>50/9 = around 5.555556</result>