The engineering team builds a road. The ratio of the length of the repaired road to the total length of the road on the first day is 1:4. If they build another 2.5 kilometers, half of the road will be completed. How many kilometers is this road in total?
工程队修一条路，第一天修的长度与这条路的总长度的比是1：4，如果再修2.5千米，就修完这条路的一半．这条路共长多少千米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2.5 / (1/4)</gadget>
<output>10</output>

<result>10</result>