The road repair team built a road and repaired 30% of the total length in 3 days. At this speed, how many days will it take to finish the rest? (answer with ratio)
修路队修一条路，3天修了全长的30%，照这样的速度，修完剩下的还需多少天？(用比例解答)
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 3</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">3 - (9/10)</gadget>
<output>21/10 = around 2.1</output>

<gadget id="calculator">(21/10) / (3/10)</gadget>
<output>7</output>

<result>7</result>