cuboid pool is 15 meters long, 8 meters wide and 1.57 meters deep. At the bottom of the pool there is an outlet pipe with an inner diameter of 2 decimeters. When the water is released, the average speed of the water flow is 2 meters per second. How many minutes does it take to empty the pool?
一个长方体水池，长15米，宽8米，深1.57米．池底有根内径为2分米的出水管．放水时，水流速度平均每秒2米．放完池中的水需要多少分钟？
<gadget id="calculator">15 * 8 * 1.57</gadget>
<output>188.4</output>

<gadget id="calculator">0.2 / 2</gadget>
<output>0.1</output>

<gadget id="calculator">0.1 ** 2</gadget>
<output>0.01</output>

<gadget id="calculator">3.14 * 0.01 * 2 * 60</gadget>
<output>3.768</output>

<gadget id="calculator">188.4 / 3.768</gadget>
<output>50</output>

<result>50</result>