Cars A and B drive opposite each other from cities A and B at the same time. After meeting each other for 8 hours, A continues to drive forward to reach city B. It will take another 4 hours. It is known that car A is faster than car B by 30 kilometers per hour. How many miles is the road between.
甲乙两车同时从AB两城市相对开出，经过8小时相遇后，甲继续向前行驶开到B城，还需要4小时，已知甲车每小时比乙车快30千米，AB两城市之间的公路长多少千米．
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

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

<gadget id="calculator">30 / 1</gadget>
<output>30</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">60 * 12</gadget>
<output>720</output>

<result>720</result>