The engineering team repaired a road, and repaired 1800 meters in 3 days. According to this working efficiency, if another 2,400 meters are repaired, the road will be completely repaired. How many days will it take to complete the road? ? (answer with ratio)
工程队修一条公路，3天修了1800米．照这样的工作效率，再修2400米，这条公路就全部修完．修完这条公路一共需要多少天？？(用比例解答)
<gadget id="calculator">1_800 + 2_400</gadget>
<output>4_200</output>

<gadget id="calculator">1_800 / 3</gadget>
<output>600</output>

<gadget id="calculator">4_200 / 600</gadget>
<output>7</output>

<result>7</result>