The ratio of the height of the three trapezoids A, B and C is 1:2:3, the ratio of the upper base is 6:9:4, and the ratio of the lower base is 12:18:8. Now that the area of A is 30, what is the sum of the areas of B and C?
甲、乙、丙三个梯形的高的比为1：2：3，上底的比为6：9：4，下底的比为12：18：8．现已知道甲的面积为30，则乙和丙的面积之和是多少．
<gadget id="calculator">6 + 12</gadget>
<output>18</output>

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

<gadget id="calculator">18 * (1/2)</gadget>
<output>9</output>

<gadget id="calculator">9 + 18</gadget>
<output>27</output>

<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">27 * 1</gadget>
<output>27</output>

<gadget id="calculator">4 + 8</gadget>
<output>12</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">12 * (3/2)</gadget>
<output>18</output>

<gadget id="calculator">27 + 18</gadget>
<output>45</output>

<gadget id="calculator">45 / 9</gadget>
<output>5</output>

<gadget id="calculator">30 * 5</gadget>
<output>150</output>

<result>150</result>