To build a canal, 15% of the total length was built in the first week, and 30% of the total length was repaired in the second week. The total length of the second and first weeks was 4,500 meters. How long is the total length of this canal?
修一条水渠，第一周修了全长的15%，第二周修了全长的30%，第二周和第一周共修4500米，这条水渠全长多少米？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/20) + (3/10)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">4_500 / (9/20)</gadget>
<output>10_000</output>

<result>10_000</result>