Wang Fei rode a bicycle to the Children's Palace, riding 12 kilometers per hour when going there, and arrived in (3/4) hours. It only took (3/5) hours to return to the original road. How many kilometers per hour did you ride on average when you returned?
王飞骑自行车去少年宫，去时每小时骑12千米，(3/4)小时到达．原路返回时只用了(3/5)小时，返回时平均每小时骑多少千米？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/4) / (3/5)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">12 * (5/4)</gadget>
<output>15</output>

<result>15</result>