Two passenger trains A and B depart from two places at the same time and meet at a distance of 40 kilometers from the midpoint after 5 hours. The express train travels 85 kilometers per hour. How many kilometers per hour does the slow train travel?
甲乙两列客车从两地同时相对开出，5小时后在距离中点40千米处相遇，快车每小时行85千米，慢车每小时行多少千米？
<gadget id="calculator">85 * 5</gadget>
<output>425</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<gadget id="calculator">425 - 80</gadget>
<output>345</output>

<gadget id="calculator">345 / 5</gadget>
<output>69</output>

<result>69</result>