Pool pump filling

A block-shaped pool that is 25 m long, 12 m wide, and 180 cm deep is to be filled with draft so that the water level is 20 cm below the edge. How long will it take to fill the pool if we use 2 pumps, each with a "power" of 125 l/min?

Final Answer:

t =  1920 min

Step-by-step explanation:

$$\begin{gathered} a=25\text{m} \\ b=12\text{m} \\ {c}_1=180\text{cm}\to \text{m}=180:100\text{m}=1.8\text{m} \\ {c}_2=20\text{cm}\to \text{m}=20:100\text{m}=0.2\text{m} \\ c=c_1-c_2=1.8-0.2=\frac{8}{5}=1.6\text{m} \\ V=a\cdot b\cdot c=25\cdot 12\cdot 1.6=480{\text{m}}^3 \\ Q=125\text{l}\to {\text{m}}^3=125:1000{\text{m}}^3=0.125{\text{m}}^3 \\ t=\frac{V}{2\cdot Q}=\frac{480}{2\cdot 0.125}=1920\text{min} \end{gathered}$$

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