A section of uphill mountain road, the total distance of this section is 12 kilometers, Kobayashi rides a bicycle uphill at 10 kilometers per hour, and downhill at 15 kilometers per hour, what is the average speed of the bicycle in kilometers?
一段上坡山路，这段路程共12千米，小林骑自行车上坡每小时行10千米，下坡每小时行15千米，求自行车的平均速度是多少千米？
<gadget id="calculator">12 / 10</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">12 / 15</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(6/5) + (4/5)</gadget>
<output>2</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<result>6</result>