A 470-meter-long train passes through a 1,030-meter-long bridge in 1 minute and 20 seconds, and then passes through a tunnel at the same speed in 40 seconds. How long is the tunnel?
一列470米长的火车，用1分20秒通过1030米长的大桥，又以同样的速度用40秒通过一隧道，隧道长几米？
<gadget id="calculator">470 + 1_030</gadget>
<output>1_500</output>

<gadget id="calculator">1_500 / 80</gadget>
<output>75/4 = around 18.75</output>

<gadget id="calculator">(75/4) * 40</gadget>
<output>750</output>

<gadget id="calculator">750 - 470</gadget>
<output>280</output>

<result>280</result>