The average speed of a car traveling between places A and B is 50 kilometers per hour. It is known to travel 55 kilometers per hour from A to B and arrive in 4 hours. How many hours did it take to return to A?
一辆汽车往返甲、乙两地的平均速度是每小时50千米．已知从甲地到乙地每小时行55千米，4小时到达．返回甲地行了多少小时？
<gadget id="calculator">2 / 50</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">55 * 4 * (1/25)</gadget>
<output>44/5 = around 8.8</output>

<gadget id="calculator">(44/5) - 4</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>