car drives from place A to place B at a speed of 100 kilometers per hour, and after arriving at place B, it drives from place B back to place A at a speed of 60 kilometers per hour. What is the average round trip speed of this car in kilometers?
一辆汽车以每小时100千米的速度从甲地开往乙地，到达乙地后，又以每小时60千米的速度从乙地开回甲地．这辆汽车往返的平均速度是多少千米．
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 100</gadget>
<output>1/100 = around 0.01</output>

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

<gadget id="calculator">(1/100) + (1/60)</gadget>
<output>2/75 = around 0.026667</output>

<gadget id="calculator">2 / (2/75)</gadget>
<output>75</output>

<result>75</result>