large truck and a small car drive from place A to place B at the same time at their respective speeds, and return immediately after arriving at place B, and their respective speeds increase by 20% when returning. 1.5 hours after departure, the car encountered a large truck on the way back. When the big truck arrives at B, the car is still (1/5) of the distance between A and B. So how many hours does it take for a car to go back and forth between A and B?
一辆大货车与一辆小轿车，分别以各自的速度同时从甲地开往乙地，到乙地后立刻返回，返回时各自的速度都提高20%．从开始出发后1.5小时，小轿车在返回的途中与大货车相遇．当大货车到达乙地时，小轿车离甲地还有甲、乙两地之间路程的(1/5)．那么小轿车在甲、乙两地之间往返一次共用多少小时？
<gadget id="calculator">1.5 / 2</gadget>
<output>0.75</output>

<gadget id="calculator">1.5 + 0.75</gadget>
<output>2.25</output>

<result>2.25</result>