There is a trapezoidal flowerbed, the upper base is 30 meters, the lower base is 40 meters, and the height is 20 meters. On average, 50 flowers are produced per square meter. How many flowers can this flower garden produce in total?
有一块梯形的花圃，上底是30米，下底是40米，高是20米．平均每平方米产鲜花50枝，这块花圃一共可以产鲜花多少枝？
<gadget id="calculator">30 + 40</gadget>
<output>70</output>

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

<gadget id="calculator">70 * 10 * 50</gadget>
<output>35_000</output>

<result>35_000</result>