Cars A and B leave opposite each other from cities A and B at the same time, and meet each other after 8 hours. After meeting, car A continues to drive to city B for another 4 hours. It is known that car A is 35 kilometers faster than car B per hour. How far is the distance between city A and city B?
甲、乙两车同时从A、B两城相对开出，经过8小时相遇．相遇后甲车继续开到B城还要4小时，已知甲车每小时比乙车快35千米，A、B两城相距多远？
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">35 / 1</gadget>
<output>35</output>

<gadget id="calculator">35 * 2</gadget>
<output>70</output>

<gadget id="calculator">70 + 35</gadget>
<output>105</output>

<gadget id="calculator">105 * 8</gadget>
<output>840</output>

<result>840</result>