A road was built in a certain city. The full length (2/5) was built in the first month, and the full length (1/4) was built in the second month. A total of 39 kilometers was built in these two months. The total length of the road How many kilometers is it?
某市修建一条公路，第一个月修了全长的(2/5)，第二个月修了全长的(1/4)，这两个月一共修了39千米，这条公路的全长是多少千米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">(2/5) + (1/4)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">39 / (13/20)</gadget>
<output>60</output>

<result>60</result>