A fast train and a slow train are traveling towards each other from A and B at the same time, and meet at a distance of 5 kilometers from the midpoint after (2/5) hours. It is known that the express train travels an average of 80 kilometers per hour, how many kilometers per hour does the slow train travel on average?
一辆快车和一辆慢车分别从A、B两地同时相向而行，经过(2/5)小时在离中点5千米处相遇．已知快车平均每小时行80千米，慢车平均每小时行多少千米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 / (2/5)</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">80 - 25</gadget>
<output>55</output>

<result>55</result>