It takes 15 seconds for a train to pass a certain electric pole, and 75 seconds to pass a 1200-meter-long bridge. So, how many meters is the length of this train?
一列火车经过某电线杆用了15秒，经过一座1200米长的大桥用了75秒，那么，这列火车的长度是多少米？
<gadget id="calculator">75 - 15</gadget>
<output>60</output>

<gadget id="calculator">1_200 / 60</gadget>
<output>20</output>

<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<result>300</result>