A trapezoidal radish field has an upper base of 15 meters, a lower base of 35 meters, and a height of 20 meters. A total of 7,500 kilograms of radishes can be harvested. How many kilograms of radishes can be harvested on average per square meter of this trapezoidal land?
一块梯形的萝卜地，上底是15米，下底是35米，高是20米，共收萝卜7500千克，这块梯形地平均每平方米收萝卜多少千克？
<gadget id="calculator">15 + 35</gadget>
<output>50</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">50 * 10</gadget>
<output>500</output>

<gadget id="calculator">7_500 / 500</gadget>
<output>15</output>

<result>15</result>