trapezoidal orchard has an upper base of 30 meters, a lower base of 90 meters, and a height of 50 meters. If each tree occupies an area of 6 square meters, how many fruit trees can be planted in this orchard?
一个梯形果园，上底30米，下底90米，高50米，如果每棵树占地6平方米，这个果园可以种多少棵果树？
<gadget id="calculator">30 + 90</gadget>
<output>120</output>

<gadget id="calculator">50 / 2 / 6</gadget>
<output>25/6 = around 4.166667</output>

<gadget id="calculator">120 * (25/6)</gadget>
<output>500</output>

<result>500</result>