A cuboid pool is 20 meters long and 9 meters wide, and the water depth in the pool is 1.57 meters. There is a water outlet pipe at the bottom of the pool. The inner diameter of the water pipe is 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 drain the water from the pool?
一个长方体水池，长20米、宽9米，池中水深1.57米．池底有根出水管，水管内直径为2分米，放水时水流速度平均每秒2米，放完这池水需要多少分钟？
<gadget id="calculator">20 * 9 * 1.57</gadget>
<output>282.6</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">282.6 / 3.768</gadget>
<output>75</output>

<result>75</result>