It takes 90 seconds for a train to pass through a 2000-meter-long bridge at a speed of 120 kilometers per hour. What is the length of the train in meters?
一列火车以每小时120千米的速度完全通过2000米长的大桥用了90秒，求火车长度多少米？
<gadget id="calculator">1 * 3_600</gadget>
<output>3_600</output>

<gadget id="calculator">1_000 / 3_600</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">120 * 1 * (5/18) * 90</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 - 2_000</gadget>
<output>1_000</output>

<result>1_000</result>