To build a section of expressway, it is planned to build 500 meters per day, which can be completed in 24 days. In actual 5 days to repair 3000 meters, how many days are actually completed? (Solution by two methods of positive and negative proportions)
修一段高速公路，计划每天修500米，24天可以完成．实际5天修3000米，实际多少天完成？(用正、反比例两种方法解)
<gadget id="calculator">12_000 / 600</gadget>
<output>20</output>

<result>20</result>