A cuboid water tank is 60 cm long and 50 cm wide when measured from the inside, and the water depth is 40 cm. There was a stone in the water tank. After taking out the stone, the depth of the water is 30 cm. What is the volume of the stone?
一个长方体水缸，从里面量长60厘米，宽50厘米，现水深40厘米，水缸里原有一块石头，把石头拿出来后水的深度为30厘米，问这块石头的体积是多少？
<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<gadget id="calculator">60 * 50 * 10</gadget>
<output>30_000</output>

<result>30_000</result>