Two boats, A and B, are sailing towards each other at points A and B of a river at the same time. A is going down the current, and B is going up against the current. When they met, the two ships A and B traveled the same distance. After the encounter, they continued to move forward. A arrived at point B. After B arrived at point A, he immediately returned by the same route. When the two ships met for the second time, ship A traveled 1 km less than ship B. , if the interval from the first encounter to the second encounter is 1 hour and 20 minutes, what is the velocity of the water flow?
甲乙两船分别在一条河的A、B两地同时相向而行，甲顺流而下，乙逆流而上．相遇时甲乙两船行了相等的航程，相遇后继续前进，甲到达B地，乙到达A地后，立即按原路返回，两船第二次相遇时，甲船比乙船少行1千米，如果从第一次相遇到第二次相遇相隔1小时20分钟，求水流速度？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<result>3/8 = around 0.375</result>