Cars A and B drive opposite each other from places A and B at the same time, meet each other after 4 hours, and car A drives another 3 hours to reach place B. It is known that car A is faster than car B by 20 kilometers per hour, and how many kilometers are there between places A and B?
甲、乙两车同时从A、B两地相对开出，4小时以后相遇，甲车再开3小时到达B地．已知甲车每小时比乙车快20千米，A、B两地相距多少千米．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 / (1/4)</gadget>
<output>80</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">80 * 7</gadget>
<output>560</output>

<result>560</result>