Cars A and B drive from places A and B at the same time and drive towards each other. When car A travels (3/5) of the whole distance, car B travels (2/3) of the whole distance. At this time, the distance between the two cars is 4 Find the distance between A and B in kilometers.
甲乙两车分别同时从A、B两地开出，相向而行，当甲车行了全程的(3/5)时，乙车行了全程的(2/3)，此时两车相距4千米，求A、B两地之间的距离．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) - 1</gadget>
<output>-1/3 = around -0.333333</output>

<gadget id="calculator">(3/5) + (-1/3)</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">4 / (4/15)</gadget>
<output>15</output>

<result>15</result>