Koizumi and Ou Ou set off from Huaxia City to OCT at the same time, and Koizumi returns immediately after arriving in OCT, and the return speed increases by 50%. Two hours after departure, Koizumi and Ou Ou met for the first time; when Ou Ou arrived in OCT, Koizumi just walked to the midpoint of the two cities. So, how many hours does it take Koizumi to go back and forth between the two cities?
小泉与欧欧同时从华夏城出发前往华侨城，小泉到达华侨城后立即返回，返回时速度提高50%．出发2小时后，小泉与欧欧第一次相遇；当欧欧到达华侨城时，小泉刚好走到两城的中点．那么，小泉在两城往返一次需要多少小时？
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<result>3</result>