Two cars, A and B, start from A and B at the same time and drive towards each other. When A has traveled 15% of the distance, B will travel 210 kilometers. It is 7:5. When two cars meet, car A travels the distance ((())/(())), how many kilometers is the distance between A and B?
甲乙两车分别从A、B两地同时出发相向而行，甲车行了这段路的15%时，乙车行210千米，两车相遇时，甲与乙两车未行的路程比是7：5．两车相遇时，甲车行了这段路的((())/(()))，A、B两地相距多少千米．
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">7 / 5</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(3/20) * (7/5)</gadget>
<output>21/100 = around 0.21</output>

<gadget id="calculator">210 / (21/100)</gadget>
<output>1_000</output>

<result>1_000</result>