A cylindrical water storage bucket has a bottom area of 20 decimeters and a height of 3 decimeters. Fill a bucket of water and pour it into another cuboid pool, which is still 20% empty. It is known that the cuboid pool has a length of 5 Decimeters, width 3 decimeters, how many decimeters is the height of the cuboid pool?
某圆柱形贮水桶，底面积为20平方分米，高为3分米，盛满一桶水，把它倒入另一个长方体水池里，水池里还空着20%，已知长方体水池长5分米，宽3分米，求长方体水池的高是多少分米？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 15 / (4/5)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 * (1/4)</gadget>
<output>5</output>

<result>5</result>