A trapezoidal piece of land, the upper base is 8 meters, the lower base is 12 meters, and the height is 50% of the sum of the upper base and the lower base. Now 30% of this land is used to plant peanuts, and the rest is planted at a ratio of 2:3. Corn and soybeans, how much area is the corn planted?
一块梯形的土地，上底为8米，下底为12米，高是上底与下底和的50%，现在这块地的30%用来种花生，剩下的部分按2：3种玉米和大豆，请问玉米种多大的面积？
<gadget id="calculator">8 + 12</gadget>
<output>20</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / 2</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 * 20 * (1/4)</gadget>
<output>100</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">100 * (3/10)</gadget>
<output>30</output>

<gadget id="calculator">100 - 30</gadget>
<output>70</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">70 * (2/5)</gadget>
<output>28</output>

<result>28</result>