The express train and the slow train depart from A and B respectively at the same time, and go towards each other, and meet on the way after 4 hours. After meeting, the two cars continued to drive forward. The slow train arrives at A and stays for 1 hour before returning to B. The express train arrives at B and stays for 2.5 hours before returning to A. It is known that it takes 12 hours for the slow train to travel from point B to point A, so how long does it take for the two cars to meet from the first meeting to the second meeting?
快车和慢车分别从甲、乙两地同时开出，相向而行，经过4小时在途中相遇．相遇后两车继续向前行驶．慢车到达甲地后停留1小时再返回乙地．快车到达乙地后停留2.5小时再返回甲地．已知慢车从乙地到甲地用了12小时，那么两车从第一次相遇到第二次相遇需要多长时间？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 - 2.5</gadget>
<output>-1.5</output>

<gadget id="calculator">12 + (-1.5)</gadget>
<output>10.5</output>

<gadget id="calculator">(1/12) * 10.5</gadget>
<output>0.875</output>

<gadget id="calculator">2 - (1/4) - 0.875</gadget>
<output>0.875</output>

<gadget id="calculator">0.875 / 0.875</gadget>
<output>1</output>

<gadget id="calculator">1 - 4</gadget>
<output>-3</output>

<gadget id="calculator">12 + 1 + (-3)</gadget>
<output>10</output>

<result>10</result>