25% of a road has been built. If another 150 meters are built, half of the road can be completed. How long is this road?
修一条路，已修了25%，如果再修150米，就可以完成这条路的一半，这条路长多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">25 / 100</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">150 / (1/4)</gadget>
<output>600</output>

<result>600</result>