The bottom area of cuboid pool A is 20 square meters, which is twice that of pool B. Pool A is filled with water and the water depth is 3m. Now pump some water from pool A and pour it into pool B so that the water depths of the two pools are the same. How many cubic meters of water should be pumped?
长方体水池甲的池底面积是20平方米，是水池乙的2倍，甲水池注满水，水深3m．现将甲水池中水抽出一些注到乙水池中，使两个水池的水深一样，要抽多少立方米的水？
<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">20 * 1</gadget>
<output>20</output>

<result>20</result>