The engineering team wanted to repair a section of road. The original plan was to repair 3.5 kilometers per day, which would take 40 days to complete; the actual repair was 0.5 kilometers more per day. How many days can it be completed in advance? (Solve with ratio)
工程队要修一段公路，原计划每天修3.5千米，40天完成；实际每天多修0.5千米．实际可以提前几天修完？(用比例解)
<gadget id="calculator">3.5 * 40</gadget>
<output>140</output>

<gadget id="calculator">3.5 + 0.5</gadget>
<output>4</output>

<gadget id="calculator">140 / 4</gadget>
<output>35</output>

<gadget id="calculator">40 - 35</gadget>
<output>5</output>

<result>5</result>