An express train and a slow train depart from AB at the same time, and meet each other in 5 hours. After meeting, the two trains continue to drive for 3 hours. At this time, the express train is still 1/4 of the distance from B, and the slow train travels a total of 680 kilometers. ． Find the distance between A and B in kilometers?
一列快车和一列慢车分别从AB两地同时相对开出，5小时相遇，相遇后两车继续行驶3小时，这时快车距B地还有全程的(1/4)，慢车共行驶680千米．求A、B两地相距多少千米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) * 3</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/5) - (3/4)</gadget>
<output>-3/20 = around -0.15</output>

<gadget id="calculator">1 + (-3/20)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">680 / (17/20)</gadget>
<output>800</output>

<result>800</result>