The distance between A and B is 120 kilometers. A bus travels from A to B at 40 kilometers per hour and returns 60 kilometers per hour on the same road. What is the average speed of the bus going back and forth between the two places? rice?
甲乙两地相距120千米，一辆公共汽车从甲地开往乙地每小时行40千米，按原路返回时每小时行60千米，这辆汽车往返两地的平均速度是多少千米？
<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<gadget id="calculator">120 / 40</gadget>
<output>3</output>

<gadget id="calculator">120 / 60</gadget>
<output>2</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">240 / 5</gadget>
<output>48</output>

<result>48</result>