To build a road, 30% of the total length was repaired in the first week, and 2/5 of the total length was repaired in the second week, and 30 kilometers were repaired less in the first week than in the second week. How many kilometers is the total length of this road?
修一条路，第一周修了全长的30%，第二周修了全长的(2/5)，第一周比第二周少修了30千米，这条路全长多少千米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) - (3/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">30 / (1/10)</gadget>
<output>300</output>

<result>300</result>