A passenger car and a truck travel towards each other from places A and B at the same time. When they meet, the bus travels 70 kilometers longer than the truck. It is known that the speed ratio of passenger cars and trucks is 7:5, how many kilometers are there between A and B?
一辆客车和一辆货车同时从甲乙两地相向而行，相遇时，客车比货车多行70千米．已知客车和货车的速度比是7：5，甲乙两地相距多少千米．
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">(7/12) - (5/12)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">70 / (1/6)</gadget>
<output>420</output>

<result>420</result>