Cars A and B drive towards each other. When A travels (1/4) of the whole journey, B travels 20 kilometers. When A arrives at B, B still has (1/5) to go. How many kilometers is the whole journey?
甲乙两车相向开出，当甲行全程的(1/4)时，乙行20千米，当甲到达乙地时，乙还有(1/5)没行，全程多少千米．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/4) * (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>