A car travels from Wuping to Longyan, traveling 40 kilometers per hour when going, and traveling 60 kilometers per hour when returning, what is the average speed of the round trip?
汽车从武平到龙岩，去时每小时行40千米，返回时每小时行60千米，往返的平均速度是多少．
<gadget id="calculator">1 * 2</gadget>
<output>2</output>

<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/40) + (1/60)</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">2 / (1/24)</gadget>
<output>48</output>

<result>48</result>