To build a canal, the full length (1/5) of the canal was built on the first day, and 450 meters on the second day, exactly three times the length of the first day. How long is this canal in meters?
修一条水渠，第一天修了全长的(1/5)，第二天修了450米，正好是第一天修的3倍，这条水渠全长多少米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">450 / 3 / (1/5)</gadget>
<output>750</output>

<result>750</result>