It took 20 seconds for a train to pass in front of Xiao Ming at a speed of 30 m/s. If the train passes a 1020m long bridge at the same speed, how many seconds will it take?
一列火车以30m/秒的速度从小明面前经过时，用去了20秒的时间．如果火车以同样的速度经过一座1020m长的大桥，共需多少秒？
<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<gadget id="calculator">600 + 1_020</gadget>
<output>1_620</output>

<gadget id="calculator">1_620 / 30</gadget>
<output>54</output>

<result>54</result>