Uncle Li delivered goods from the city to the countryside. It took 3 hours to go, 40 kilometers per hour, and 2 hours to return. How many kilometers per hour did he travel on average when he returned?
李叔叔从城里往乡村送货物，去的时候用了3小时，每小时行40千米，返回时间用了2小时，返回时平均每小时行多少千米？
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">3 * 20</gadget>
<output>60</output>

<result>60</result>