The road repair team completed a section of road in three days, 40% of the total length on the first day, 2.5 kilometers on the second day, and 1/2 of the total length on the third day. How long is this section of road in kilometers?
修路队三天修完一段公路，第一天修了全长的40%，第二天修了2.5千米，第三天修了全长的(1/2)，这段公路长是多少千米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (2/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2.5 / (1/10)</gadget>
<output>25</output>

<result>25</result>