A car goes from a certain city to a provincial capital to pick up goods, travels an average of 75 kilometers per hour, and arrives in 2 hours. It took 3 hours to return along the original road after filling up the goods. How many kilometers per hour was the average travel time when returning?
一辆汽车从某城去省城拉货，去时平均每小时行75千米，2小时到达．装满货后沿原路返回用了3小时，返回时平均每小时行几千米？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">75 * (2/3)</gadget>
<output>50</output>

<result>50</result>