Qianqian rode a bicycle from home to a forest park far away from home. In the first hour, she drove 25% of the whole journey. Arriving at the forest park, how many kilometers did Qianqian drive from the departure to the forest park?
芊芊从家里骑车去一个离家较远的森林公园，第一个小时行驶了全程的25%，第二个小时比第一个小时多行驶了5千米，又行驶了15千米之后才到达森林公园，芊芊从出发到森林公园一共行驶了多少千米？
<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4) - (1/4)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / (1/2)</gadget>
<output>40</output>

<result>40</result>