Xiaohong went from A to B to do business, and traveled the whole distance (3/7), and he traveled another 20 kilometers. At this time, the ratio of the distance he traveled to the distance he did not travel was 5:2. How many kilometers has Xiaohong traveled?
小红从甲地到乙地办事，行了全程的(3/7)，他又行了20千米，这时他行的路程与未行的路程的比是5：2．小红行了多少千米？
<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(5/7) - (3/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">20 / (2/7)</gadget>
<output>70</output>

<gadget id="calculator">70 * (3/7)</gadget>
<output>30</output>

<gadget id="calculator">30 + 20</gadget>
<output>50</output>

<result>50</result>