The distance between A and B is 360 kilometers. A car travels from A to B at 60 kilometers per hour. When returning from B to A, it is raining and travels 40 kilometers per hour. Find the average round trip speed of the car.
甲乙两地相距360千米，一辆汽车从甲地开往乙地，每小时行60千米，由乙地返回甲地时由于下雨，每小时行40千米．求这辆汽车往返的平均速度．
<gadget id="calculator">360 * 2</gadget>
<output>720</output>

<gadget id="calculator">360 / 60</gadget>
<output>6</output>

<gadget id="calculator">360 / 40</gadget>
<output>9</output>

<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<gadget id="calculator">720 / 15</gadget>
<output>48</output>

<result>48</result>