car travels from A to B, travels 52 kilometers per hour, arrives at B in 4.5 hours, and returns to A in 3.5 hours when returning to the original road. Find out how long the car travels between A and B average speed.
一辆汽车由甲地去乙地，去时每小时行驶52千米，4.5小时到达乙地，原路返回时，用了3.5小时回到甲地，求这辆汽车往返甲、乙两地的平均速度．
<gadget id="calculator">4.5 + 3.5</gadget>
<output>8</output>

<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">52 * 4.5 * (1/4)</gadget>
<output>58.5</output>

<result>58.5</result>