Car A and car B leave from cities A and B at the same time. After driving for 4 hours, car A travels 80% of the whole journey, and car B exceeds the midpoint by 150 kilometers. It is known that car A travels 30 kilometers more per hour than car B, how many kilometers is the distance between cities A and B?
甲、乙两车分别从A、B两城同时相对开出，行驶4小时后，甲车行了全程的80%，乙车超过中点150千米．已知甲车比乙车每小时多行30千米，求A、B两城相距多少千米？
<gadget id="calculator">4 * 30</gadget>
<output>120</output>

<gadget id="calculator">150 + 120</gadget>
<output>270</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/5) - (1/2)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">270 / (3/10)</gadget>
<output>900</output>

<result>900</result>