Two cars, fast and slow, travel towards each other from places A and B respectively, and continue to move forward after meeting each other. When the distance between the two cars is 210 kilometers, the fast car has traveled (3/4) the entire distance, and the slow train has traveled (3/5) the entire distance. How many kilometers are there between A and B?
快慢两车分别从甲乙两地相向而行，相遇后继续前进，在两车相距210千米时，快车行了全程的(3/4)，慢车行了全程的(3/5)，求甲乙两地相距多少千米？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) - 1</gadget>
<output>-2/5 = around -0.4</output>

<gadget id="calculator">(3/4) + (-2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">210 / (7/20)</gadget>
<output>600</output>

<result>600</result>