A cylindrical bucket, if the height is half of the original and the diameter of the bottom is twice the original, it can hold 40 kg of water, how many kg of water can it originally hold?
一个圆柱形水桶，若将高改为原来的一半，底面直径为原来的2倍，可装水40千克，那么原来可装水多少千克？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">40 / 4</gadget>
<output>10</output>

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

<result>20</result>