A road has been repaired (1/4), B has repaired 30%, and there are still 9 kilometers left. What is the total length of this road?
一条路，甲修了(1/4)，乙修了30%，还剩下9千米，这条路全长是多少？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/4) + (3/10)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">1 - (11/20)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">9 / (9/20)</gadget>
<output>20</output>

<result>20</result>