Two vehicles, A and B, start from AB at the same time and go towards each other. When A has traveled (3/20) of AB's distance, B has traveled (1/5) of AB's distance; when A is still AB away from B At (1/4) of the distance, car B just arrives at point A and returns immediately. When car A arrives at point B, how much is the distance AB between car B and point B.
甲乙两车同时从AB两地出发相向而行，当甲车行了AB路程的(3/20)时，乙车行了AB路程的(1/5)；当甲车距B地还有AB路程的(1/4)的时候，乙车正好到达A地，立即返回．当甲车到达B地时，乙车距B地还有AB路程的多少．
<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

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

<gadget id="calculator">(3/20) / (1/5)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / (3/4)</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">(4/3) - 1</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>