A cuboid water tank with a length of 40 cm, a width of 30 cm and a height of 30 cm is filled with water of 20 cm deep. Now put a square cuboid iron block with a height of 50 cm and a side length of 20 cm into the water tank vertically. The water surface in the tank How many centimeters will it rise?
在一个长40cm，宽30cm，高30cm的长方体水箱中注有20cm深的水，现把一块高是50cm，底面边长是20cm的正方形的长方体铁块竖直放入水箱中，水箱中的水面会升高多少厘米？
<gadget id="calculator">40 * 30</gadget>
<output>1_200</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<gadget id="calculator">1_200 - 400</gadget>
<output>800</output>

<gadget id="calculator">20 / 800</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">40 * 30 * (1/40)</gadget>
<output>30</output>

<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<result>10</result>