Answer: 50 hours
Step-by-step explanation:
Given
The volume of a swimming pool is [tex]25,000[/tex] gallon
It takes 30 minutes to fill [tex]250\ \text{gallons}[/tex]
Using Unitary method
[tex]\Rightarrow 250\ \text{gallon takes}\rightarrow 30\ \text{minutes}\\\Rightarrow 1\ \text{gallon takes}\rightarrow \dfrac{30}{250}\\\\\Rightarrow 25,000\ \text{gallon}\rightarrow \dfrac{30}{250}\times 25,000=3000\ \text{minutes or 50 hours}[/tex]