Two cars A and B leave opposite each other from AB at the same time. They meet each other in 4 hours. Car A travels to B in another 3 hours. It is known that car A is 20 kilometers faster than car B every hour. How many kilometers is the distance between AB and AB?
甲乙两车同时从AB两地相对开出，4小时相遇，甲车再行3小时到B地，已知甲车每小时比乙车块20千米，AB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>