The distance between A and B is 156 kilometers. A car starts from A and travels downhill, arrives at B in 5.2 hours, and then returns to A along the original road from B. It takes 2.6 hours longer than before. Find this car The average speed of the car to and fro.
甲、乙两地相距156千米，一辆汽车从甲地出发下坡而行，5.2小时到达乙地，又从乙地沿原路上坡返回甲地，比去时多用2.6小时，求这辆汽车往返的平均速度．
<gadget id="calculator">5.2 + 5.2 + 2.6</gadget>
<output>13</output>

<gadget id="calculator">2 / 13</gadget>
<output>2/13 = around 0.153846</output>

<gadget id="calculator">156 * (2/13)</gadget>
<output>24</output>

<result>24</result>