Two cars leave opposite places A and B at the same time, move forward at a constant speed, and meet each other in 8 hours. It takes 12 hours for the express train to go from A to B, how long does it take for the slow train to get from B to A? (Solve using the ratio method).
两车同时从甲、乙两地相对开出，匀速前行，8小时相遇．快车从甲地到乙地用了12时，慢车从乙地用多长时间才能到达甲地？(用比例方法解答)．
<gadget id="calculator">12 * 8</gadget>
<output>96</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">96 / 4</gadget>
<output>24</output>

<result>24</result>