Cars A and B drive respectively from cities A and B opposite each other. After 4 hours, car A travels (1/2) of the whole journey, and car B travels 1/4 of the whole journey (1/4) 40 kilometers longer. Known The car travels 20 kilometers more per hour than the second car. How many kilometers are the distance between A and B?
甲乙两车分别从A，B两城相对开出，经过4小时，甲车行了全程的(1/2)，乙车行了全程的(1/4)又多40千米，已知甲车比乙车每小时多行20千米，A，B两城相距多少千米？
<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">40 + 80</gadget>
<output>120</output>

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

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">120 / (1/4)</gadget>
<output>480</output>

<result>480</result>