To build a road, 30 kilometers have been built, which is 25% of the unbuilt road. How long is this road in total?
修一条公路，已经修了30千米，是未修的25%．这条公路一共多长？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">30 / (1/4)</gadget>
<output>120</output>

<gadget id="calculator">120 + 30</gadget>
<output>150</output>

<result>150</result>