Uncle Li set off from the county seat to Shangzhuang to deliver fertilizers. It took 3 hours to go and 2 hours to return. Given that the going speed is 50 km/h, how many kilometers per hour will it travel on average when returning?
李叔叔从县城出发去上庄送化肥，去的时候用了3小时，返回时用了2小时．已知去时的速度为50千米/时，返回时平均每小时行多少千米？
<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">3 * 25</gadget>
<output>75</output>

<result>75</result>